1 GNU Autoconf NEWS - User visible changes.
3 * Noteworthy changes in release ?.? (????-??-??) [?]
5 ** Backward incompatibilities:
7 *** Warnings about obsolete constructs are now on by default.
9 These warnings can be turned off with ‘-Wno-obsolete’.
11 Many of these warnings advise maintainers to run autoupdate.
12 Be aware that autoupdate cannot solve all backward compatibility
13 problems, and cannot completely solve all of the problems it does
14 address. A configure script edited by autoupdate is likely to
15 need further manual fix-ups.
17 *** Many macros have become pickier about argument quotation.
19 If you get a shell syntax error from your generated configure
20 script, or seemingly impossible misbehavior (e.g. entire blocks of
21 the configure script not getting executed), check first that all
22 macro arguments are properly quoted. The “M4 Quotation” section of
23 the manual explains how to quote macro arguments properly.
25 It is unfortunately not possible for autoupdate to correct
28 *** Many macros no longer AC_REQUIRE as many other macros as they used to.
30 This can expose several classes of latent bugs. These are the ones
33 - Make sure to explicitly invoke all of the macros that set result
34 variables used later in the configure script, or in generated
37 - Autoconf macros that use AC_REQUIRE are not safe to use in shell
38 control-flow constructs that appear outside of macros defined by
39 AC_DEFUN. Use AS_IF, AS_CASE, etc. instead. (See the
40 “Prerequisite Macros” section of the manual for details.)
42 The set of macros that use AC_REQUIRE internally may change from
43 release to release. The only macros that are guaranteed *not* to
44 use AC_REQUIRE are the macros for acting on the results of a
45 test: AC_DEFINE, AC_SUBST, AC_MSG_*, AC_CACHE_CHECK, etc.
47 - AC_REQUIRE cannot be applied to macros that need to be used with
48 arguments. Instead, invoke the macro normally, with its arguments.
50 *** More macros use config.sub and config.guess internally.
52 As a consequence of improved support for cross compilation (see below),
53 more macros now use the auxiliary scripts ‘config.sub’ and ‘config.guess’.
54 If you use any of the affected macros, these scripts must be available
55 when your configure script is run, even if you have no intention of
56 ever cross-compiling your program.
58 autoreconf will issue an error if any auxiliary scripts are needed but
59 cannot be found. (It is not currently possible to make autoconf
60 itself issue this error.)
62 ‘autoreconf --install’ will add ‘config.sub’, ‘config.guess’, and
63 ‘install-sh’ to your source tree if they are needed. If you are
64 using Automake, scripts added to your tree by ‘autoreconf --install’
65 will automatically be included in the tarball produced by ‘make dist’;
66 otherwise, you will need to arrange for them to be distributed
69 See the “Input” section of the manual for more detail, including
70 where to get the auxiliary scripts that may be needed by autoconf macros.
72 *** Older versions of automake and aclocal (< 1.8) are no longer supported.
74 *** AC_CONFIG_SUBDIRS no longer directly supports Cygnus configure.
76 If you are still using an Autoconf script to drive configuration of
77 a multi-package build tree where some subdirectories use Cygnus
78 configure, copy or link $ac_aux_dir/configure into each subdirectory
79 where it is needed. Please also contact us; we were under the
80 impression nobody used this very old tool anymore.
82 *** AC_CHECK_HEADER and AC_CHECK_HEADERS only do a compilation test.
84 This completes the transition from preprocessor-based header tests
85 begun in Autoconf 2.56.
87 The double test that was the default since Autoconf 2.64 is no
88 longer available. You can still request a preprocessor-only test
89 by specifying [-] as the fourth argument to either macro, but this
90 is now deprecated. If you really need that behavior use
93 *** AC_INCLUDES_DEFAULT assumes an ISO C90 compliant C implementation.
95 Specifically, it assumes that the ISO C90 headers <stdlib.h> and
96 <string.h> are available, without checking for them, and does not
97 include the pre-standard header <memory.h> at all. If the POSIX
98 header <strings.h> exists, it will be included, without testing
99 whether it is safe to include both <string.h> and <strings.h> in the
102 For compatibility’s sake, the C preprocessor macros STDC_HEADERS,
103 HAVE_STDLIB_H, and HAVE_STRING_H are defined unconditionally.
104 These preprocessor macros should be considered obsolescent.
106 Future releases of Autoconf may reduce the set of headers checked
107 for by AC_INCLUDES_DEFAULT.
109 *** AS_ECHO and AS_ECHO_N unconditionally use ‘printf’.
111 This is substantially simpler, more reliable, and, in most cases,
112 faster than attempting to use ‘echo’ at all. However, if ‘printf’
113 is not a shell builtin, configure scripts will run noticeably
114 slower, and if ‘printf’ is not available at all, they will crash.
115 The only systems where this is known to be a problem are extremely
116 old, and unlikely to be able to handle modern C programs for other
117 reasons (e.g. not having a C90-compliant compiler at all).
119 *** Configure scripts require support for $( ... ) command substitution.
121 This POSIX shell feature is approximately the same age as
122 user-defined functions, but there do exist shells that support
123 functions and not $( ... ), such as Solaris 10 /bin/sh.
125 Configure scripts will automatically locate a shell that supports
126 this feature and re-execute themselves with it, if necessary, so
127 the new requirement should be transparent to most users.
129 In this release, most of Autoconf’s code still uses the older `...`
130 notation for command substitution.
132 *** AC_INIT now trims extra white space from its arguments.
134 For instance, AC_INIT([ GNU Hello ], [1.0]) will set PACKAGE_NAME
137 *** Macros that take whitespace-separated lists as arguments
138 now always expand macros within those arguments.
140 Formerly, these macros would *usually* expand those arguments, but
141 the behavior was not reliable nor was it consistent between autoconf
144 Macro expansion within these arguments is deprecated; if expansion
145 changes the list, a warning in the “obsolete” category will be
146 emitted. Note that ‘dnl’ is a macro. Putting ‘dnl’ comments inside
147 any argument to an Autoconf macro is, in general, only supported
148 when that argument takes more Autoconf code (e.g. the ACTION-IF-TRUE
149 argument to AC_COMPILE_IFELSE).
151 The affected macros are AC_CHECK_FILES, AC_CHECK_FUNCS,
152 AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS, AC_CHECK_HEADERS_ONCE,
153 AC_CONFIG_MACRO_DIRS, AC_CONFIG_SUBDIRS, and AC_REPLACE_FUNCS.
155 *** AC_FUNC_VFORK no longer ignores a signal-handling bug in Solaris 2.4.
157 This bug was being ignored because Emacs wanted to use ‘vfork’ on
158 Solaris 2.4 anyway, but current versions of Emacs have dropped
159 support for Solaris 2.4. Most programs will want to avoid ‘vfork’
160 on this OS because of this bug.
162 *** AC_FUNC_STRERROR_R assumes strerror_r is unavailable if it’s not declared.
164 The fallback technique it used to probe strerror_r’s return type
165 when the function was present in the C library, but not declared by
166 <string.h>, was fragile and did not work at all when cross-compiling.
167 The systems where this fallback was necessary were all obsolete.
169 Programs that use AC_FUNC_STRERROR_R should make sure to test the
170 preprocessor macro HAVE_DECL_STRERROR_R before using strerror_r at all.
172 *** AC_OPENMP can’t be used if you have files named ‘mp’ or ‘penmp’.
174 Autoconf will now issue an error if AC_OPENMP is used in a configure
175 script that’s in the same directory as a file named ‘mp’ or ‘penmp’.
176 Configure scripts that use AC_OPENMP will now error out upon
177 encountering files with these names in their working directory
178 (e.g. when the build directory is separate from the source directory).
180 If you have files with these names at the top level of your source
181 tree, we recommend either renaming them or moving them into a
182 subdirectory. See the documentation of AC_OPENMP for further
187 *** Configure scripts now support a ‘--runstatedir’ option.
189 This defaults to ‘${localstatedir}/run’. It can be used, for
190 instance, to place per-process temporary runtime files (such as pid
191 files) into ‘/run’ instead of ‘/var/run’.
193 *** autoreconf will now run gtkdocize and intltoolize when appropriate.
195 *** autoreconf now recognizes AM_GNU_GETTEXT_REQUIRE_VERSION.
197 This macro can be used with gettext 0.19.6 or later to specify
198 a *minimum* version requirement for gettext, instead of the *fixed*
199 version requirement specified by AM_GNU_GETTEXT_VERSION.
201 *** autoheader handles secondary config headers better.
203 It is no longer necessary to duplicate AC_DEFINE templates in the
204 main configuration header for autoheader to notice them.
206 *** AC_PROG_CC now enables C2011 mode if the compiler supports it.
208 If not, it will fall back to C99 and C89, as before. Similarly,
209 AC_PROG_CXX now enables C++2011 if available, falling back on C++98.
211 *** New macro AC_C__GENERIC tests for C2011 _Generic support.
213 *** AC_C_VARARRAYS has been aligned with C2011.
215 It now defines __STDC_NO_VLA__ if variable-length arrays are not
216 supported but the compiler does not define __STDC_NO_VLA__.
218 For backward compatibility with Autoconf 2.61-2.69 AC_C_VARARRAYS
219 still defines HAVE_C_VARARRAYS, but this result macro is obsolescent.
221 *** New macro AC_CONFIG_MACRO_DIRS.
223 This macro can be used more than once and accepts a list of
224 directories to search for local M4 macros. With Automake 1.13 and
225 later, use of this macro eliminates a reason to use ACLOCAL_AMFLAGS
228 The older AC_CONFIG_MACRO_DIR, which could only be used once, is
229 still supported but considered deprecated.
231 *** AC_USE_SYSTEM_EXTENSIONS knows about more extensions to enable.
233 System extensions will now be enabled on HP-UX, macOS, and MINIX.
234 Optional ISO C library components (e.g. decimal floating point) will
237 *** New compatibility macro AC_CHECK_INCLUDES_DEFAULT.
239 This macro runs the checks normally performed as a side-effect by
240 AC_INCLUDES_DEFAULT, if they haven’t already been done. Autoupdate
241 will replace certain obsolete constructs, whose only remaining
242 useful effect is to trigger those checks, with this macro. It is
243 unlikely to be useful otherwise.
245 *** AC_REQUIRE_AUX_FILE has been improved.
247 Configure scripts now check, on startup, for the availability of all
248 the aux files that were mentioned in an AC_REQUIRE_AUX_FILE
249 invocation. This should help prevent certain classes of packaging
252 Also, it is no longer necessary for third-party macros that use
253 AC_REQUIRE_AUX_FILE to mention AC_CONFIG_AUX_DIR_DEFAULT. However,
254 if you are using AC_CONFIG_AUX_DIR_DEFAULT *without* also using
255 AC_REQUIRE_AUX_FILE, please start using AC_REQUIRE_AUX_FILE to
256 specify the aux files you actually need, so that the check can be
259 *** AC_PROG_LEX has an option to not look for yywrap.
261 AC_PROG_LEX now takes one argument, which may be either ‘yywrap’ or
262 ‘noyywrap’. If it is ‘noyywrap’, AC_PROG_LEX will only set LEXLIB
263 to ‘-lfl’ or ‘-ll’ if a scanner that defines both main and yywrap
264 itself still needs something else from that library. On the other
265 hand, if it is ‘yywrap’, AC_PROG_LEX will fail (setting LEX to ‘:’
266 and LEXLIB to nothing) if it can’t find a library that defines yywrap.
268 In the absence of arguments, AC_PROG_LEX’s behavior is bug-compatible
269 with 2.69, which did neither of the above things (see the manual for
270 details). This mode is deprecated.
272 We encourage all programs that use AC_PROG_LEX to use the new
273 ‘noyywrap’ mode, and to define yywrap themselves, or use %noyywrap.
274 The yywrap function in lib(f)l is trivial, and self-contained
275 scanners are easier to work with.
277 ** Obsolete features and new warnings
279 *** Use of the long-deprecated name ‘configure.in’ for the autoconf
280 input file now elicits a warning in the “obsolete” category.
282 *** Use of the undocumented internal shell variables $as_echo and
283 $as_echo_n now elicits a warning in the “obsolete” category.
284 The macros AS_ECHO and AS_ECHO_N should be used instead.
286 *** autoconf will now issue warnings (in the “syntax” category)
287 if the input file is missing a call to AC_INIT and/or AC_OUTPUT.
289 *** autoconf will now issue warnings (in the “syntax” category)
290 for a non-literal URL argument to AC_INIT, and for a TARNAME
291 argument to AC_INIT which is either non-literal or contains
292 characters that should not be used in file names (e.g. ‘*’).
294 *** AC_PROG_CC_STDC, AC_PROG_CC_C89, AC_PROG_CC_C99 are now obsolete.
296 Applications should use AC_PROG_CC.
298 *** AC_HEADER_STDC and AC_HEADER_TIME are now stubs.
300 They still define the C preprocessor macros STDC_HEADERS and
301 TIME_WITH_SYS_TIME, respectively, but they no longer check for the
302 ancient, non-ISO-C90 compliant systems where formerly those macros
303 would not be defined. Autoupdate will remove them.
305 These macros were already labeled obsolete in the manual.
307 *** AC_DIAGNOSE, AC_FATAL, AC_WARNING, and _AC_COMPUTE_INT are now
308 replaced with modern equivalents by autoupdate.
310 These macros were already labeled obsolete in the manual.
312 *** AC_CONFIG_HEADER is now diagnosed as obsolete, and replaced with
313 AC_CONFIG_HEADERS by autoupdate.
315 This macro has been considered obsolete for many years and was not
318 *** The macro AC_OBSOLETE is obsolete.
320 Autoupdate will replace it with m4_warn([obsolete], [explanation]).
321 If possible, macros using AC_OBSOLETE should be converted to use
322 AU_DEFUN or AU_ALIAS instead, which enables autoupdate to replace
323 them, but this has to be done by hand and is not always possible.
325 This macro has been considered obsolete for many years, but was not
326 officially declared as such.
328 *** Man pages for config.guess and config.sub are no longer provided.
330 They were moved to the master source tree for config.guess and
335 *** Compatible with current Automake, Libtool, Perl, Texinfo, and shells.
337 All of autoconf’s tools and generated scripts, and the build process
338 and testsuite for autoconf itself, have been tested to work
339 correctly with current versions of Automake, Libtool, Perl, Texinfo,
340 bash, ksh93, zsh, and FreeBSD and NetBSD /bin/sh.
342 Generated configure scripts are expected to work reliably with an
343 even wider variety of shells, including BusyBox sh and various
344 proprietary Unixes’ /bin/sh, as long as they are minimally compliant
345 with the Unix95 shell specification. Notably, support for
346 shell-script functions and the ‘printf’ builtin are required.
348 *** Checks compatible with current language standards and compilers.
350 Many individual macros have been improved to accommodate changes in
351 recent versions of the C and C++ language standards, and new
352 features and quirks of commonly used compilers (both free and
355 *** Improved support for cross compilation.
357 Many individual macros have been improved to produce more accurate
358 results when cross-compiling.
360 *** Improved robustness against unusual build environments.
362 Many bugs have been fixed where generated configure scripts would
363 fail catastrophically under unusual conditions, such as stdout being
364 closed, or $TMPDIR not being an absolute path, or the root directory
365 being mentioned in $PATH.
367 *** AC_CHECK_FUNCS_ONCE and AC_CHECK_HEADERS_ONCE now support multiple
368 programming languages. They no longer perform all checks in the
369 language active upon the first use of the macro.
371 *** AC_CHECK_DECL and AC_CHECK_DECLS will now detect missing declarations for
372 library functions that are also Clang compiler builtins.
374 *** AC_PATH_X and AC_PATH_XTRA don’t search for X11 when cross-compiling.
376 Libraries and headers found by running xmkmf or searching /usr/X11,
377 /usr/X11R7, etc. are likely to belong to a native X11 installation
378 for the build machine and to be inappropriate for cross compilation.
380 To cross-compile programs that require X11, we recommend putting the
381 headers and libraries for the host system in your cross-compiler’s
382 default search paths. Alternatively, use configure’s --x-includes
383 and --x-libraries command line options to tell it where they are.
385 *** AC_PROG_CC is now defined via AC_DEFUN_ONCE.
387 This means configure scripts will no longer check repeatedly for the
388 C compiler under some combinations of macro use.
390 *** AS_IF’s if-false argument may be empty after macro expansion.
392 This long-standing limitation broke configure scripts that used
393 macros in this position that emitted shell code in 2.69 but no
394 longer do, so we have lifted it.
396 *** AC_HEADER_MAJOR detects the location of the major, minor, and
397 makedev macros correctly under glibc 2.25 and later.
399 *** AC_FC_LINE_LENGTH now documents the maximum portable length of
400 “unlimited” Fortran source code lines to be 250 columns, not 254.
402 *** AC_INIT and AS_INIT no longer embed (part of) the path to the
403 source directory in generated files.
405 We believe this was the only case where generated file contents
406 could change depending on the environment outside the source tree
407 itself. If you find any other cases please report them as bugs.
409 *** config.log properly escapes arguments in the header comment.
411 *** config.status --config output is now quoted in a more readable fashion.
413 ** Autotest enhancements
415 *** Autotest provides a new macro AT_DATA_UNQUOTED, similar to AT_DATA
416 but processing variable substitutions, command substitutions and
417 backslashes in the contents argument.
419 *** AC_CONFIG_TESTDIR will automatically pass EXEEXT to a testsuite (via
422 *** AT_TESTED arguments can use variable or command substitutions, including
423 in particular $EXEEXT
425 * Noteworthy changes in release 2.69 (2012-04-24) [stable]
427 ** Autoconf now requires perl 5.6 or better (but generated configure
428 scripts continue to run without perl).
430 * Noteworthy changes in release 2.68b (2012-03-01) [beta]
431 Released by Eric Blake, based on git versions 2.68.*.
433 ** Autoconf-generated configure scripts now unconditionally re-execute
434 themselves with $CONFIG_SHELL, if that's set in the environment.
436 ** The texinfo documentation no longer specifies "front-cover" or
437 "back-cover" texts, so that it may now be included in Debian's
440 ** Support for the Go programming language has been added. The new macro
441 AC_LANG_GO sets variables GOC and GOFLAGS.
443 ** AS_LITERAL_IF again treats '=' as a literal. Regression introduced in
446 ** The macro AS_EXECUTABLE_P, present since 2.50, is now documented.
450 - AC_PROG_LN_S and AS_LN_S now fall back on 'cp -pR' (not 'cp -p') if 'ln -s'
451 does not work. This works better for symlinks to directories.
453 - New macro AC_HEADER_CHECK_STDBOOL.
455 - New and updated macros for Fortran support:
457 AC_FC_CHECK_BOUNDS to enable array bounds checking
458 AC_F77_IMPLICIT_NONE and AC_FC_IMPLICIT_NONE to disable implicit integer
459 AC_FC_MODULE_EXTENSION to compute the Fortran 90 module name extension
460 AC_FC_MODULE_FLAG for the Fortran 90 module search path flag
461 AC_FC_MODULE_OUTPUT_FLAG for the Fortran 90 module output directory flag
462 AC_FC_PP_SRCEXT for preprocessed Fortran source files extensions
463 AC_FC_PP_DEFINE for the Fortran preprocessor define flag
465 * Noteworthy changes in release 2.68 (2010-09-22) [stable]
466 Released by Eric Blake, based on git versions 2.67.*.
468 ** AC_MSG_ERROR (and AS_ERROR) can once again be followed immediately by
469 `dnl'. Regression introduced in 2.66.
471 ** AC_INIT again allows URLs with '?' for its BUG-REPORT argument.
472 Regression introduced in 2.66.
474 ** AC_REPLACE_FUNCS again allows a non-literal argument, such as a shell
475 variable that expands to a list of functions to check. Regression
478 ** AT_BANNER() with empty argument will cause visual separation from previous
481 ** The macros AC_PREPROC_IFELSE, AC_COMPILE_IFELSE, AC_LINK_IFELSE, and
482 AC_RUN_IFELSE now warn if the first argument failed to use
483 AC_LANG_SOURCE or AC_LANG_PROGRAM to generate the conftest file
484 contents. A new macro AC_LANG_DEFINES_PROVIDED exists if you have
485 a compelling reason why you cannot use AC_LANG_SOURCE but must
488 ** The macro m4_define_default is now documented.
490 ** Symlinked config.cache files are supported; configure now tries to
491 update non-symlinked cache files atomically, so that concurrent configure
492 runs do not leave behind broken cache files. It is still unspecified
493 which subset or union of results is cached though.
495 ** Autotest testsuites should not contain long text lines any more, and be
496 portable even when very many test groups are used.
498 ** AT_CHECK semantics with respect to the Autotest variable $at_status and
499 shell execution environment of the arguments are documented now.
501 ** AC_FC_LIBRARY_LDFLAGS now tolerates output from newer gfortran.
503 ** Newly obsolete macros
504 The following macros have been marked obsolete. New programs
505 should use the corresponding Gnulib modules. Gnulib not only
506 detects a larger set of portability problems with these functions,
507 but also provides complete workarounds.
509 AC_FUNC_ERROR_AT_LINE AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK
510 AC_FUNC_MKTIME AC_FUNC_STRTOD
513 * Major changes in Autoconf 2.67 (2010-07-21) [stable]
514 Released by Eric Blake, based on git versions 2.66.*.
516 ** AC_CONFIG_SUBDIRS with more than one subdirectory at a time works again.
517 Regression introduced in 2.66.
519 ** AC_CHECK_SIZEOF of a pointer type works again. Regression introduced in
522 ** New macro AC_FC_LINE_LENGTH to accept long Fortran source code lines.
524 ** AC_PREPROC_IFELSE now keeps the preprocessed output in the conftest.i
525 file for inspection by the commands in the ACTION-IF-TRUE argument.
527 ** AC_INIT again allows parentheses and other characters that are literal
528 in single- or double-quoted strings, and in quoted and unquoted
529 here-documents, for its PACKAGE and VERSION arguments. Regression
532 ** autoreconf passes warning flags to new enough versions of aclocal.
534 ** Running an Autotest testsuite in parallel mode no longer triggers a
535 race condition that could cause the testsuite run to end early,
536 fixing a sporadic failure in autoconf's own testsuite. Bug present
537 since introduction of parallel tests in 2.63b.
540 * Major changes in Autoconf 2.66 (2010-07-02) [stable]
541 Released by Eric Blake, based on git versions 2.65.*.
543 ** AC_FUNC_MMAP works in C++ mode again. Regression introduced in 2.65.
545 ** Use of m4_divert without a named diversion now issues a syntax warning,
546 since it is seldom right to change diversions behind autoconf's back.
548 ** The macros AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, and
549 AC_TYPE_INT64_T work again. Regression introduced in 2.65.
551 ** AC_PROG_INSTALL correctly uses `shtool' again. Regression introduced
554 ** Autoconf should work on EBCDIC hosts.
556 ** AC_CHECK_DECL and AC_CHECK_DECLS accept optional function argument types
557 for overloaded C++ functions.
559 ** AS_SET_CATFILE accepts nonliterals in its variable name argument now.
561 ** Autotest testsuites accept an option --recheck to rerun tests that
562 failed or passed unexpectedly during the last non-debug testsuite run.
564 ** AC_ARG_ENABLE and AC_ARG_WITH now also accept `+' signs in `--enable-*'
565 and `--with-*' arguments, converting them to underscores for the variable
568 ** In configure scripts, loading CONFIG_SITE no longer searches PATH,
569 and problems in loading the configuration site files are diagnosed.
571 ** Autotest testsuites may optionally provide colored test results.
573 ** The previously undocumented Autotest macros AT_ARG_OPTION and
574 AT_ARG_OPTION_ARG have seen bug fixes and are documented now.
575 AT_ARG_OPTION has been changed in that the negative of a long option
576 --OPTION is now --no-OPTION rather than --noOPTION.
578 ** The macro AS_LITERAL_IF is slightly more conservative; text
579 containing shell quotes are no longer treated as literals.
580 Furthermore, a new macro, AS_LITERAL_WORD_IF, adds an additional
581 level of checking that no whitespace occurs in literals.
583 ** The macros AS_TR_SH and AS_TR_CPP no longer expand their results.
585 ** The following macros are now documented:
588 ** New macro AC_FC_FIXEDFORM to accept fixed-form Fortran.
591 * Major changes in Autoconf 2.65 (2009-11-21) [stable]
592 Released by Eric Blake, based on git versions 2.64.*.
594 ** Autoconf is now licensed under the General Public License version 3
595 or later (GPLv3+). As with earlier versions, the license includes
596 an exception clause so that you may release a configure script
597 generated by autoconf under the license of your own program.
599 ** New macros to support Objective C++.
600 AC_PROG_OBJCXX AC_PROG_OBJCXXCPP
602 ** The following undocumented autoconf macros, removed in Autoconf 2.64,
603 have been reinstated:
606 These macros are present only for backwards compatibility purposes.
608 ** The macro AC_LANG_COMPILER no longer fails on embedded systems that
609 lack fopen in the C library, such as AVR or RTEMS (regression
612 ** The AC_FC_FREEFORM macro no longer suffers from a whitespace bug that
613 made it fail with some Fortran compilers (regression introduced in
616 ** The AC_TYPE_UINT64_T and AC_TYPE_INT64_T macros have been fixed to no
617 longer mistakenly select a 32-bit type on some compilers (bug present
618 since macros were introduced in 2.59c).
620 ** The AC_FUNC_MMAP macro has been fixed to be portable to systems like
621 Cygwin (bug present since macro was introduced in 2.0).
623 ** The following documented autotest macros are new:
626 ** The following m4sugar macros now quote their expansion:
627 m4_toupper m4_tolower
629 ** The following m4sugar macros are new:
632 ** The m4sugar macro m4_text_wrap now copes with embedded quoting without
633 requiring quadrigraphs. For uses like AC_ARG_VAR([a], [[b c]]),
634 this gives the intuitive behavior of "[b c]" in the output (2.63
635 gave the output of "[b], [c]", and 2.64 encountered a failure).
637 ** The `$tmp' temporary directory used in config.status is documented for
640 ** config.status now provides a --config option to produce the configuration.
642 ** Many cache variables used by Autoconf's macros are now documented.
644 ** Configure scripts work better on DJGPP by avoiding a bug present in
645 the DJGPP port of bash 2.04 in handling 'return' in a shell
646 function (regression introduced in 2.64).
648 * Major changes in Autoconf 2.64 (2009-07-26) [stable]
649 Released by Eric Blake, based on git versions 2.63b.*.
651 ** Autoconf now requires GNU M4 1.4.6 or later. Earlier versions of M4
652 have a bug in regular expression handling that interferes with some
653 of the speedups provided since Autoconf 2.63. GNU M4 1.4.13 or
654 later is recommended.
656 ** AS_IF and AS_CASE have been taught to avoid syntax errors even when
657 given arguments that expand to just whitespace.
659 ** The following documented autoconf macros are new:
660 AC_ERLANG_SUBST_ERTS_VER
662 ** The autoheader tool now understands m4 macro arguments passed to
663 AC_DEFINE and AC_DEFINE_UNQUOTED.
665 ** Ensure AT_CHECK can support commands that include a # given with
666 proper m4 quoting. For shell comments, this is a new feature; for
667 non-shell comments, this fixes a regression introduced in 2.63b.
668 Additionally, AT_CHECK correctly supplies shell escapes for
669 metacharacters occurring in m4 macro expansions within the expected
670 stdout and stderr parameters.
672 ** The macro AT_CHECK now understands the concept of hard failure. If
673 a test exits with an unexpected status 99, cleanup actions for the
674 test are inhibited and the test is treated as a failure regardless
675 of AT_XFAIL_IF. It also understands the new directives
676 ignore-nolog, stdout-nolog, and stderr-nolog.
678 ** The following documented autotest macros are new:
679 AT_CHECK_UNQUOTED AT_FAIL_IF AT_SKIP_IF
681 ** The following documented m4sugar macros are new:
682 m4_argn m4_copy_force m4_default_nblank m4_default_nblank_quoted
683 m4_ifblank m4_ifnblank m4_rename_force
685 ** The autoconf testsuite now exercises all Erlang macros.
687 * Major changes in Autoconf 2.63b (2009-03-31) [beta]
688 Released by Eric Blake, based on git versions 2.63.*.
690 ** The manual is now shipped under the terms of the GNU FDL 1.3.
692 ** AC_REQUIRE now detects the case of an outer macro which first expands
693 then later indirectly requires the same inner macro. Previously,
694 this case led to silent out-of-order expansion (bug present since
695 2.50); it now issues a syntax warning, and duplicates the expansion
696 of the inner macro to guarantee dependencies have been met. See
697 the manual for advice on how to refactor macros in order to avoid
698 the bug in earlier autoconf versions and avoid increased script
699 size in the current version.
701 ** AC_DEFUN_ONCE has improved semantics. Previously, a macro declared
702 with AC_DEFUN_ONCE warned on a second invocation; and out-of-order
703 expansion was still possible. Now, dependencies are guaranteed,
704 and subsequent invocations are a silent no-op. This makes
705 AC_DEFUN_ONCE an ideal macro for silencing AC_REQUIRE warnings.
707 ** The following macros are now defined with AC_DEFUN_ONCE. This means
708 a subtle change in semantics; previously, an AC_DEFUN macro could
709 expand one of these macros multiple times or surround the macro
710 inside shell conditional text to bypass the effects of these
711 macros, but now the macro will expand exactly once, and prior to
712 the start of any enclosing AC_DEFUN macro:
713 AC_CANONICAL_BUILD AC_CANONICAL_HOST AC_CANONICAL_TARGET
714 AC_HEADER_ASSERT AC_PROG_INSTALL AC_PROG_MKDIR_P
715 AC_USE_SYSTEM_EXTENSIONS
717 ** AC_LANG_ERLANG works once again (regression introduced in 2.61a).
719 ** AC_HEADER_ASSERT is fixed so that './configure --enable-assert' no
720 longer mistakenly disables assertions.
722 ** AC_INIT now takes an optional fifth parameter that can be used to
723 set AC_PACKAGE_URL, a URL for the package's home page; the URL is
724 used in `configure --help' and is also available via AC_DEFINE.
726 ** Autotest testsuites accept an option --jobs[=N] for parallel testing.
727 This feature is still in testing, and may not work on every
728 platform, help in improving it would be appreciated.
730 ** Autotest testsuites do not attempt to write startup error messages
731 to the log file before that is opened (regression introduced in 2.63).
733 ** Configure scripts now use shell functions. This feature leads to
734 smaller configure files and faster execution.
736 ** Present But Cannot Be Compiled: Autoconf will now proceed with
737 the compiler's result if a header is present but cannot be compiled.
738 The warning is still printed, and you should really fix it by
739 providing a fourth parameter to AC_CHECK_HEADER/AC_CHECK_HEADERS.
741 ** Autoreconf added aclocal to the set of programs affected by the
742 `autoreconf -I dir' option.
744 ** The following documented m4sugar macros are new:
745 m4_chomp m4_chomp_all m4_cleardivert m4_curry m4_default_quoted
746 m4_esyscmd_s m4_map_args m4_map_args_pair m4_map_args_sep
747 m4_map_args_w m4_set_map m4_set_map_sep m4_stack_foreach
748 m4_stack_foreach_lifo m4_stack_foreach_sep
749 m4_stack_foreach_sep_lifo
751 ** The following m4sugar macros are documented now, but in some cases
752 with slightly different semantics than what the previous
753 undocumented version had:
754 m4_copy m4_dumpdefs m4_rename m4_version_prereq
756 ** The m4sugar macro m4_expand has been taught to handle unterminated
757 comments and shell case statements. As a result, it is used
758 internally in more places, such as AC_DEFINE and AT_CHECK. Most
759 uses of AC_DEFINE and AT_CHECK should not behave any differently;
760 however, it may be necessary to add double-quoting around
761 unbalanced `(' where single-quoting used to be sufficient.
763 ** The following documented m4sh macros are new:
764 AS_INIT_GENERATED AS_LINENO_PREPARE AS_ME_PREPARE AS_SET_STATUS
765 AS_VAR_APPEND AS_VAR_ARITH AS_VAR_COPY
767 ** The following m4sh macros are documented now, but in some cases
768 with slightly different semantics than what the previous
769 undocumented version had:
770 AS_ECHO AS_ECHO_N AS_ESCAPE AS_EXIT AS_LITERAL_IF AS_UNSET
771 AS_VAR_IF AS_VAR_POPDEF AS_VAR_PUSHDEF AS_VAR_SET AS_VAR_SET_IF
772 AS_VAR_TEST_SET AS_VERSION_COMPARE
774 ** The m4sh macros AS_IF and AS_CASE can now be used in shell lists.
775 The responsibility for supplying a trailing newline now belongs to
776 the call site, but since most users did not add dnl, this generally
777 results in fewer empty lines in configure.
780 * Major changes in Autoconf 2.63 (2008-09-09) [stable]
781 Released by Eric Blake, based on git versions 2.62.*.
783 ** AC_C_BIGENDIAN does not mistakenly report "universal" for some
784 bigendian hosts, a regression introduced with universal binary
787 ** AC_PATH_X now includes /lib64 and /usr/lib64 in its list of default
790 ** AC_USE_SYSTEM_EXTENSIONS no longer conflicts with an external
791 AC_DEFINE([__EXTENSIONS__]). This fixes a regression introduced in
792 2.62 when using macros such as AC_AIX that were made obsolete in
793 favor of the more portable AC_USE_SYSTEM_EXTENSIONS.
795 ** AC_CHECK_TARGET_TOOLS is usable in the non-cross-compile case.
797 ** Newly obsolete macros
798 The following macro has been marked obsolete, since current porting
799 targets can safely assume C89 semantics that signal handlers return
800 void. We have no current plans to remove the macro.
804 ** The macros m4_map and m4_map_sep now ignore any list elements
805 consisting of just empty quotes, and m4_map_sep now expands its
806 separator. This fixes a regression in 2.62 when these macros were
807 first documented, for the sake of clients expecting the semantics
808 that these macros had prior to that time. The new macros m4_mapall
809 and m4_mapall_sep, along with extra quoting of the separator, can
810 be used to get the semantics that m4_map_sep had in 2.62.
812 ** Clients of m4_expand, such as AS_HELP_STRING and AT_SETUP, can now
813 handle properly quoted but otherwise unbalanced parentheses (for
814 some macros, this fixes a regression in 2.62).
816 ** Two new quadrigraphs have been introduced: @{:@ for (, and @:}@ for ),
817 allowing the output of unbalanced parentheses in more contexts.
819 ** The following m4sugar macros are new:
820 m4_cleardivert m4_joinall m4_mapall m4_mapall_sep m4_reverse
821 m4_set_add m4_set_add_all m4_set_contains m4_set_contents
822 m4_set_delete m4_set_difference m4_set_dump m4_set_empty
823 m4_set_foreach m4_set_intersection m4_set_list m4_set_listc
824 m4_set_remove m4_set_size m4_set_union
826 ** The following m4sugar macros now accept multiple arguments, as is the
827 case with underlying m4:
828 m4_defn m4_popdef m4_undefine
830 ** The following m4sugar macros now guarantee linear scaling; they
831 previously had linear scaling with m4 1.6 but quadratic scaling
832 when using m4 1.4.x. All macros built on top of these also gain
833 the scaling improvements.
834 m4_bmatch m4_bpatsubsts m4_case m4_cond m4_do m4_dquote_elt
835 m4_foreach m4_join m4_list_cmp m4_map m4_map_sep m4_max
838 ** AT_KEYWORDS once again performs expansion on its argument, such that
839 AT_KEYWORDS([m4_if([$1], [], [default])]) no longer complains about
840 the possibly unexpanded m4_if [regression introduced in 2.62].
842 ** Config header templates `#undef UNDEFINED /* comment */' do not lead to
843 nested comments any more; regression introduced in 2.62.
846 * Major changes in Autoconf 2.62 (2008-04-05) [stable]
847 Released by Eric Blake, based on git versions 2.61a.*.
849 ** Many optimizations have been applied to make overall execution faster.
851 ** Autotest now makes use of shell functions.
853 ** config.status now uses awk instead of sed also for config headers.
855 - As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
856 values, i.e., backslash-newline combinations are handled correctly.
857 Further, for config headers, the total size of values is not limited by
858 the POSIX length limit of text lines any more, only each single line.
860 ** New config variable `top_build_prefix'.
862 ** New Autoconf macros:
863 AC_AUTOCONF_VERSION AC_OPENMP AC_PATH_PROGS_FEATURE_CHECK
865 ** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.
867 ** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
868 like '__restrict' if the variant spelling is available, as this is
869 more likely to work when mixing C and C++ code.
871 ** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
872 be a string of tokens such that "T y;" is a valid member declaration
875 ** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
876 is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.
878 ** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
879 they did not work for function types. In C++, they now work on any
880 type-id that can be the operand of sizeof; this is similar to C,
881 except it excludes anonymous struct and union types. Formerly,
882 some (but not all) C++ types involving anonymous struct and union
883 were accepted, though this was not documented.
885 ** AC_CONFIG_LINKS now prefers to link against files in the build tree
886 if found, and it works to link against a file of the same name in
887 the source tree, even if both trees coincide.
889 ** AC_INIT no longer alters $@; regression introduced in 2.60.
891 ** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.
893 ** AS_HELP_STRING no longer underquotes its first argument; it also handles
894 the case where the first argument contains single-quoted commas.
895 For example, "AS_HELP_STRING([-a, [--arg[=foo]]], [bar])" produces:
896 " -a, --arg[=foo] bar"
897 Additionally, the macro now takes two additional arguments,
898 indent-column and wrap-column; these should not normally be needed,
899 but can be used to fine-tune how the output text is wrapped.
901 ** AC_PROG_INSTALL now requires an install program that can install multiple
902 files into a target directory.
904 ** The command 'autoconf -' now correctly processes a file from stdin.
906 ** 'autoreconf -m' now honors $MAKE.
908 ** For all of the directory arguments for 'configure', such as '--prefix'
909 or '--bindir', trailing slashes are stripped. As an example, if
910 tab completion in the user's shell appends trailing slashes, the
911 command './configure --prefix=/usr/' will still result in an
912 expanded libdir value of /usr/lib, not /usr//lib.
914 ** `configure --help=recursive' now works in read-only trees and from
915 unconfigured build trees.
917 ** If precious variables differ only in whitespace, then the cache consistency
918 check warns instead of fails, and reuses the old value.
920 ** AT_BANNER is now documented.
922 ** AT_SETUP now handles macro expansions properly when calculating line
925 ** Autotest now determines $srcdir correctly.
927 ** Testsuites built by autotest now accept a -C/--directory=DIR option
928 to adjust the working directory prior to creating files.
930 ** Autoconf now requires GNU M4 1.4.5 or later. Earlier versions of M4 have
931 a bug in macro tracing that interferes with the interaction between
932 Autoconf and Automake. GNU M4 1.4.11 or later is recommended. The
933 configure search for a working M4 is improved.
935 ** For portability with the eventual M4 2.0, macros should no longer use
936 anything larger than $9 to refer to arguments.
938 ** Documentation for m4sugar is improved.
940 - The following macros were previously available as undocumented
941 interfaces; the macros are now documented as stable interfaces.
943 __oline__ m4_assert m4_bmatch m4_bpatsubsts m4_car m4_case
944 m4_cdr m4_default m4_divert_once m4_divert_pop m4_divert_push
945 m4_divert_text m4_do m4_errprintn m4_fatal m4_flatten
946 m4_ifndef m4_ifset m4_ifval m4_ifvaln m4_location
947 m4_n m4_shiftn m4_strip m4_warn
949 - The following macros were previously available as undocumented
950 interfaces, but had bug fixes or semantic changes as part of this
951 release. Packages that relied on the undocumented behavior
952 should be analyzed to make sure they will still work with the
953 new documented behavior.
955 m4_cmp m4_list_cmp m4_join m4_map m4_map_sep m4_sign
956 m4_text_box m4_text_wrap m4_version_compare
958 - The m4_wrap macro used to have unspecified order, but now
959 guarantees FIFO order. m4_wrap_lifo was added to guarantee LIFO
962 - Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
963 should consider using the new AC_AUTOCONF_VERSION instead.
965 - m4sugar macros that are not documented in the manual are still
966 deemed experimental, and should not be used outside of Autoconf.
968 ** The m4sugar macros m4_append and m4_append_uniq, first documented in
969 2.60, have been fixed to treat both the string and the separator
970 arguments consistently with regards to quoting. Prior to this fix,
971 m4_append_uniq could mistakenly duplicate entries if the expansion
972 of the separator resulted in a different string (for example, if it
973 contained quotes, a comma, or a macro name). However, it means
974 that programs previously using
975 m4_append([name], [string], [[, ]])
976 are now using a four-character separator instead of the intended
977 comma and space. If you need portability to earlier versions of
978 Autoconf, you can insert the following snippet after AC_INIT but
979 before any other macro expansions, to enforce the new semantics:
980 m4_pushdef([m4_append], [m4_define([$1],
981 m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
982 Additionally, m4_append_uniq now takes optional parameters that can
983 be used to take action depending on whether anything was appended,
984 and warns if a non-empty separator occurs within the string being
985 appended, since that can lead to duplicates.
987 ** The following m4sugar macros are new:
988 m4_append_uniq_w m4_apply m4_combine m4_cond m4_count
989 m4_dquote_elt m4_echo m4_expand m4_ignore m4_make_list m4_max
990 m4_min m4_newline m4_shift2 m4_shift3 m4_unquote m4_wrap_lifo
992 ** Warnings are now generated by default when an installer invokes
993 'configure' with an unknown --enable-* or --with-* option.
994 These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
995 macro, or by invoking 'configure' with --disable-option-checking.
997 ** Existing obsolete macros
998 The documentation for the following macros is adjusted to make it
999 more clear that they have previously been marked obsolete, as their
1000 functionality can be accomplished by other macros. We have no
1001 current plans to remove them from Autoconf.
1003 AC_ENABLE AC_STRUCT_ST_BLKSIZE AC_STRUCT_ST_RDEV AC_WITH
1005 ** Newly obsolete macros
1006 The following macros have been marked obsolete, as they only
1007 perform a subset of AC_USE_SYSTEM_EXTENSIONS. We have no current
1008 plans to remove them.
1010 AC_AIX AC_GNU_SOURCE AC_ISC_POSIX AC_MINIX
1012 ** AC_C_LONG_DOUBLE is obsolescent.
1013 The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
1014 tests for problems that are so old that it is no longer of
1015 practical importance on current systems. New programs need not use
1016 AC_C_LONG_DOUBLE. We have no current plans to remove it.
1018 ** AC_DIAGNOSE, AC_WARNING, and AC_FATAL are obsolescent.
1019 The documentation now favors the use of M4sugar macros m4_warn and
1020 m4_fatal, since the naming makes it more obvious that the
1021 diagnostics are associated with M4 expansion (ie. when running
1022 `autoconf'), and offers less confusion with the AC_MSG_ERROR,
1023 AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
1024 when running `configure'. We have no current plans to remove these
1028 * Major changes in Autoconf 2.61a (2006-12-11)
1030 ** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
1031 on many platforms. This has been fixed.
1033 ** AC_FUNC_SETVBUF_REVERSED is now obsolete. It is still defined for backward
1034 compatibility but it does nothing. The macro was already
1035 obsolescent, as the last systems to have the problem were those
1036 based on SVR2, which became obsolete in 1987. The macro had bugs
1037 on some modern systems and could no longer be maintained reliably
1038 due to lack of ancient systems to test it on.
1040 ** config.status now uses awk instead of sed for most substitutions, for speed.
1042 - As a side effect multi-line values of substituted variables no
1043 longer have a small limit in total size, though for portability
1044 each line should not exceed the POSIX length limit for text lines.
1046 - It is now documented that Makefile.in should not contain
1047 overlapping variable occurrences, e.g., @VAR1@VAR2@.
1048 Autoconf's behavior was always iffy in such cases, and the
1049 awk implementation has changed the behavior.
1051 ** Many uses of 'echo' have been rewritten so that Autoconf-generated
1052 scripts have fewer problems with strings or file names containing
1053 embedded special characters such as backslash or leading "-". This
1054 was implemented by using `printf '%s\n' "$foo"' instead of `echo
1055 "$foo"' when printf works. Due to the implementation technique
1056 used, Autoconf-generated scripts now run considerably more slowly
1057 on ancient implementations lacking printf. However, this should
1058 not be a problem, since Autoconf-generated scripts in practice
1059 invariably find a more-modern shell these days.
1062 * Major changes in Autoconf 2.61 (2006-11-17)
1064 ** New macros AC_C_FLEXIBLE_ARRAY_MEMBER, AC_C_VARARRAYS.
1066 ** AC_ARG_ENABLE and AC_ARG_WITH now allow '.' in feature and package names.
1069 * Major changes in Autoconf 2.60b (2006-10-22)
1072 Autoconf-generated shell scripts no longer export BIN_SH, due to
1073 configuration hassles with this. Installers who need BIN_SH in
1074 their environment should set it before invoking 'configure' and
1075 'make'. As far as we know, this affects only Unixware installations.
1077 ** Obsolescent macros
1078 The documentation now says that the following macros are obsolescent,
1079 as they are superseded by Gnulib:
1081 AC_FUNC_FNMATCH AC_FUNC_FNMATCH_GNU AC_FUNC_GETLOADVG AC_REPLACE_FNMATCH
1083 New programs should use the Gnulib counterparts of these macros.
1084 We have no current plans to remove them from Autoconf.
1086 ** AC_COMPUTE_INT no longer caches or reports results.
1088 ** AC_CHECK_DECL now also works with aggregate objects.
1090 ** AC_USE_SYSTEM_EXTENSIONS now defines _TANDEM_SOURCE for NonStop platforms.
1092 ** GNU M4 1.4.7 or later is now recommended.
1095 New M4sugar macro, which is more secure than the POSIX M4 maketemp.
1098 Now an alias for m4_mkstemp.
1100 * Major changes in Autoconf 2.60a (2006-08-25)
1102 ** GNU M4 1.4.6 or later is now recommended.
1104 ** The check for C99 now tests for varargs macros, as documented.
1105 It also tests that the preprocessor supports 64-bit integers.
1107 ** Autoconf now uses constructs like "#ifdef HAVE_STDLIB_H" rather than
1108 "#if HAVE_STDLIB_H", so that it now works with "gcc -Wundef -Werror".
1110 ** The functionality of the undocumented _AC_COMPUTE_INT is now provided
1111 by a public and documented macro, AC_COMPUTE_INT. The parameters to the
1112 two macros are different, so autoupdate will not change the old private name
1113 to the new one. _AC_COMPUTE_INT may be removed in a future release.
1115 ** AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT now require
1116 that long long types be at least 64 bits wide, as C99 and tradition
1117 requires. Formerly, they accepted implementations of any width.
1120 * Major changes in Autoconf 2.60
1122 Released 2006-06-23, by Ralf Wildenhues.
1124 ** Autoconf no longer depends on whether m4wrap is FIFO (as Posix requires)
1125 or LIFO (as in GNU M4 1.4.x). GNU M4 2.0 is expected to conform to Posix
1126 here, so m4wrap/m4_wrap users should no longer depend on LIFO behavior.
1128 ** Provide a way to turn off warnings about the changed directory variables.
1130 * Major changes in Autoconf 2.59d
1132 Released 2006-06-05, by Ralf Wildenhues.
1134 ** GNU make now recommended for VPATH builds
1135 INSTALL now suggests VPATH builds (e.g., "sh ../srcdir/configure")
1136 only if you use GNU make. In practice, other 'make' implementations
1137 have too many subtle incompatibilities in their support for VPATH.
1138 Many packages (including Autoconf itself) are portable to other
1139 'make' implementations, but some packages are not, and recommending
1140 GNU make keeps the installation instructions simpler.
1142 ** Even more safety checks for the new Directory variables:
1143 Warn about suspicious `${datarootdir}' found in config files output.
1145 ** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
1146 These never-documented macros and variables have been marked with
1147 comments saying that they may be removed in a future release,
1148 because their use can lead to unintended code being executed.
1149 If you need functionality that only these macros or variables
1150 currently supply, please write bug-autoconf@gnu.org.
1152 ** AC_SUBST, AC_DEFINE
1153 Literal arguments to these are passed to m4_pattern_allow now.
1156 Passing 'ac_cv_prog_cc_stdc=no' to 'configure' now sets ac_cv_prog_cc_c99
1157 and ac_cv_prog_cc_c89 to 'no' as well, for backward compatibility with
1158 obsolete K&R tests in the Automake test suite.
1167 Now more robust with special characters in file names, or when
1168 multiple processes create the same directory at the same time.
1170 ** Obsolescent macros
1171 The documentation now says that the following macros are obsolescent:
1172 they test for problems that are so old that they are no longer of
1173 practical importance on current systems.
1175 AC_C_BACKSLASH_A AC_FUNC_MEMCMP AC_HEADER_DIRENT
1176 AC_C_CONST AC_FUNC_SELECT_ARGTYPES AC_HEADER_STAT
1177 AC_C_PROTOTYPES AC_FUNC_SETPGRP AC_HEADER_STDC
1178 AC_C_STRINGIZE AC_FUNC_SETVBUF_REVERSED AC_HEADER_SYS_WAIT
1179 AC_C_VOLATILE AC_FUNC_STAT AC_HEADER_TIME
1180 AC_FUNC_CLOSEDIR_VOID AC_FUNC_STRFTIME AC_ISC_POSIX
1181 AC_FUNC_GETPGRP AC_FUNC_UTIME_NULL AC_PROG_GCC_TRADITIONAL
1182 AC_FUNC_LSTAT AC_FUNC_VPRINTF AC_STRUCT_TM
1184 New programs need not use these macros. We have no current plans to
1188 For compatibility with future Libtool 2.0, autoreconf will invoke
1189 libtoolize with the option `--ltdl' now, if LT_CONFIG_LTDL_DIR is
1192 * Major changes in Autoconf 2.59c
1194 Released 2006-04-12, by Ralf Wildenhues.
1196 ** The configure command now redirects standard input from /dev/null,
1197 to help avoid problems with subsidiary commands that might mistakenly
1198 read standard input. AS_ORIGINAL_STDIN_FD points to the original
1199 standard input before this redirection, if you really want configure to
1200 read from standard input.
1202 ** Directory variables adjusted to recent changes in the GNU Coding Standards.
1203 The following directory variables are new:
1205 datarootdir read-only architecture-independent data root [PREFIX/share]
1206 localedir locale-specific message catalogs [DATAROOTDIR/locale]
1207 docdir documentation root [DATAROOTDIR/doc/PACKAGE]
1208 htmldir html documentation [DOCDIR]
1209 dvidir dvi documentation [DOCDIR]
1210 pdfdir pdf documentation [DOCDIR]
1211 psdir ps documentation [DOCDIR]
1213 The following variables have new default values:
1215 datadir read-only architecture-independent data [DATAROOTDIR]
1216 infodir info documentation [DATAROOTDIR/info]
1217 mandir man documentation [DATAROOTDIR/man]
1219 This means that if you use any of `@datadir@', `@infodir@', or
1220 `@mandir@' in a file, you will have to ensure `${datarootdir}' is
1221 defined in this file. As a temporary measure, if any of those are
1222 found but no mention of `datarootdir', the substitutions will be
1223 replaced with values that do not contain `${datarootdir}', and a
1224 warning will be issued.
1226 ** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
1227 a trailing slash. Similar change will be made to ac_top_builddir in a
1228 future release; the old style value, which matches (../)*, is (and will
1229 continue to be) available as ac_top_build_prefix.
1232 New macro to check for support of 'typeof' syntax a la GNU C.
1234 ** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
1235 New "once-only" variants of commonly-used macros, to make 'configure'
1236 smaller and faster in common cases.
1239 New macro to check for strtold with C99 semantics.
1242 New macro that lets builder disable assertions at 'configure'-time.
1245 Now checks for X11/Xlib.h and XrmInitialize (X proper) rather than
1246 X11/Intrinsic.h and XtMalloc (Xt).
1248 ** AC_PRESERVE_HELP_ORDER
1249 New macro that causes `configure' to display help strings for AC_ARG_ENABLE
1250 and AC_ARG_WITH arguments in one region, in the order defined. The default
1251 behavior is to group options of each classes separately.
1253 ** AC_PROG_CC, AC_PROG_CXX
1254 No longer automatically arrange to declare the 'exit' function of C,
1255 when a C++ compiler is used. Standard Autoconf macros no longer use
1256 'exit', so this is no longer an issue for them. If you use C++, and
1257 want to call 'exit', you'll have to arrange for its declaration
1258 yourself. But we now suggest you return from 'main' instead.
1260 ** AC_PROG_CC_C89, AC_PROG_CC_C99
1261 New macros for ISO C99 support. AC_PROG_CC_C89 and AC_PROG_CC_C99
1262 check for ANSI C89 and ISO C99 support respectively.
1265 Has been unobsoleted, and will check if the compiler supports ISO
1266 C99, falling back to ANSI C89 if not. ac_cv_prog_cc_stdc is
1267 retained for backwards compatibility, assuming the value of
1268 ac_cv_prog_cc_c99 or ac_cv_prog_cc_c89 (whichever is valid, in
1271 ** AC_STRUCT_DIRENT_D_INO, AC_STRUCT_DIRENT_D_TYPE
1272 New macros for checking commonly-used members of struct dirent.
1275 The substituted value can now contain newlines.
1278 The substitution now occurs only when @variable@ is on a line by itself,
1279 optionally surrounded by spaces and tabs. The whole line is replaced.
1281 ** AC_TYPE_LONG_DOUBLE, AC_TYPE_LONG_DOUBLE_WIDER
1282 New macros to check for long double, and whether it is wider than double.
1283 The old macro AC_C_TYPE_LONG_DOUBLE has been marked as obsolete;
1284 applications should switch to the new macro.
1286 ** AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, AC_TYPE_INT64_T,
1287 AC_TYPE_INTMAX_T, AC_TYPE_INTPTR_T, AC_TYPE_LONG_LONG_INT, AC_TYPE_SSIZE_T,
1288 AC_TYPE_UINT8_T, AC_TYPE_UINT16_T, AC_TYPE_UINT32_T, AC_TYPE_UINT64_T,
1289 AC_TYPE_UINTMAX_T, AC_TYPE_UINTPTR_T, AC_TYPE_UNSIGNED_LONG_LONG_INT
1290 New macros to check for C99 and POSIX types.
1292 ** AC_USE_SYSTEM_EXTENSIONS
1293 New macro to enable extensions to Posix.
1296 New macro which is defined to the name of the first declared config header
1297 or undefined if no config headers have been declared yet.
1300 The macro correctly handles quadrigraphs now.
1302 ** AS_BOURNE_COMPATIBLE, AS_SHELL_SANITIZE, AS_CASE
1303 These macros are new or published now.
1306 New macro for copyright notices in testsuite files.
1308 ** ALLOCA, LIBOBJS, LTLIBOBJS
1309 Object names added to these variables are now prefixed with `${LIBOBJDIR}',
1310 as in `${LIBOBJDIR}alloca.o'. LIBOBJDIR is meant to be defined from
1311 `Makefile.in' in case the object files lie in a different directory.
1312 The LIBOBJDIR feature is experimental.
1315 Supports --no-recursive now.
1317 ** New macros to support Erlang/OTP.
1318 New macros for configuring paths to Erlang tools and libraries:
1319 AC_ERLANG_PATH_ERLC, AC_ERLANG_NEED_ERLC, AC_ERLANG_PATH_ERL,
1320 AC_ERLANG_NEED_ERL, AC_ERLANG_CHECK_LIB, AC_ERLANG_SUBST_ROOT_DIR,
1321 AC_ERLANG_SUBST_LIB_DIR.
1323 New macros for configuring installation of Erlang libraries:
1324 AC_ERLANG_SUBST_INSTALL_LIB_DIR, AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR.
1326 ** The manual now mentions Gnulib more prominently.
1328 ** New macros to support Objective C.
1329 AC_PROG_OBJC, AC_PROG_OBJCPP.
1331 * Major changes in Autoconf 2.59b
1333 Released 2004-08-20, by Paul Eggert.
1336 New macro that computes the default alignment of a type.
1338 ** AC_CHECK_TOOL, AC_PATH_TOOL, AC_CHECK_TOOLS
1339 When cross-compiling, these macros will give a warning if the tool
1340 is not prefixed. In the future, unprefixed cross tools will not
1341 be detected; please consult the info documentation for information
1342 about the reason of this change.
1344 ** AC_CHECK_TARGET_TOOL, AC_PATH_TARGET_TOOL, AC_CHECK_TARGET_TOOLS
1345 New macros that detect programs whose name is prefixed with the
1346 target type, if the build type and target type are different.
1348 ** AC_REQUIRE_AUX_FILE
1349 New trace macro that declares expected auxiliary files.
1352 New macro that tests for a grep program that accepts as a long a line
1355 ** AC_PROG_EGREP, AC_PROG_FGREP
1356 These macros now require AC_PROG_GREP, and try EGREP="$GREP -E" and
1357 FGREP="$GREP -F" respectively if possible, or else run a path search for
1358 a program that accepts as long a line as possible.
1361 New macro that tests for a sed program that truncates as few characters
1364 * Major changes in Autoconf 2.59
1366 Released 2003-11-04, by Akim Demaille
1368 ** ac_abs_builddir etc.
1369 Absolute file names were actually relative in 2.58.
1371 * Major changes in Autoconf 2.58
1373 Released 2003-11-04, by Akim Demaille
1376 core.* files are no longer removed, as they may be valid user files.
1378 ** autoreconf and auxiliary directory
1379 Autoreconf creates the auxiliary directory if needed. This is
1380 especially useful for initial "bootstrapping" of fresh CVS checkouts.
1382 ** AC_CONFIG_MACRO_DIR
1383 Use this macro to declare the directory for local M4 macros for aclocal.
1386 No longer includes twice the same file in LIBOBJS if invoked
1389 ** AC_CONFIG_COMMANDS
1390 The directory for its first argument is automatically created. For
1393 AC_CONFIG_COMMANDS([src/modules.hh], [...])
1395 $top_builddir/src/ is created if needed.
1397 ** Autotest and local.at
1398 The optional file local.at is always included in Autotest test suites.
1401 The warnings are always issued, including with cached runs.
1402 This became a significant problem since aclocal and automake can
1403 run autoconf behind the scene.
1405 ** autoheader warnings
1406 The warnings of autoheader can be turned off, using --warning.
1407 For instance, -Wno-obsolete disables the complaints about acconfig.h
1408 and other deprecated constructs.
1411 AC_C_RESTRICT, AC_INCLUDES_DEFAULT, AC_LANG_ASSERT, AC_LANG_WERROR,
1414 ** AC_DECL_SYS_SIGLIST
1418 Now checks that mktime is the inverse of localtime.
1420 ** Improve DJGPP portability
1421 The Autoconf tools and configure behave better under DJGPP.
1423 ** Present But Cannot Be Compiled
1424 New FAQ section dedicated to the mystic
1426 configure: WARNING: pi.h: present but cannot be compiled
1427 configure: WARNING: pi.h: check for missing prerequisite headers?
1428 configure: WARNING: pi.h: proceeding with the preprocessor's result
1431 ** Concurrent executions of autom4te
1432 autom4te now locks its internal files, which enables concurrent
1433 executions of autom4te, likely to happen if automake, autoconf,
1434 autoheader etc. are run simultaneously.
1437 Use of Libtool 1.5 and higher is encouraged. Compatibility with
1438 Libtool pre-1.4 is not checked.
1441 Testsuites no longer rerun failed tests in verbose mode; instead,
1442 failures are logged while the test is run.
1444 In addition, expected failures can be marked as such.
1446 * Major changes in Autoconf 2.57
1448 Released 2002-12-03 by Paul Eggert.
1450 Bug fixes for problems with AIX linker, with freestanding C compilers,
1451 with GNU M4 limitations, and with obsolete copies of GNU documents.
1453 The Free Documentation License has been upgraded from 1.1 to 1.2.
1455 * Major changes in Autoconf 2.56
1457 Released 2002-11-15 by Akim Demaille.
1459 One packaging problem fixed (config/install-sh was not executable).
1461 * Major changes in Autoconf 2.55
1463 Released 2002-11-14 by Akim Demaille.
1467 Have your configure.ac checked by autoscan ("autoscan").
1468 Try the warning options ("autoreconf -fv -Wall").
1472 - AC_CHECK_HEADER, AC_CHECK_HEADERS
1473 More information on proper use.
1475 - Writing Test Programs
1477 This sections explains how to write good test sources to use with
1478 AC_COMPILE_IFELSE etc. It documents AC_LANG_PROGRAM and so forth.
1480 - AC_FOO_IFELSE vs. AC_TRY_FOO
1482 Explains why Autoconf moves from AC_TRY_COMPILE etc. to
1483 AC_COMPILE_IFELSE and AC_LANG_PROGRAM etc.
1487 - Is more robust to different Gettext installations.
1489 - Produces messages (when --verbose) to be understood by Emacs'
1492 - Supports -W/--warnings.
1495 Once the GNU Build System reinstalled, run `./config.status
1496 --recheck && ./config.status && make' if possible.
1500 - Supports --cache, and --no-cache.
1502 - ~/.autom4te.cfg makes it possible to disable the caching mechanism
1503 (autom4te.cache). See `Customizing autom4te' in the documentation.
1510 Support for the obsoleted options -m, --macrodir, -l, --localdir is
1511 dropped in favor of the safer --include/--prepend-include scheme.
1516 AC_COMPILER_IFELSE, AC_FUNC_MBRTOWC, AC_HEADER_STDBOOL,
1517 AC_LANG_CONFTEST, AC_LANG_SOURCE, AC_LANG_PROGRAM, AC_LANG_CALL,
1518 AC_LANG_FUNC_TRY_LINK, AC_MSG_FAILURE, AC_PREPROC_IFELSE.
1521 Obsoleted macros are kept for Autoconf backward compatibility, but
1522 should be avoided in configure.ac. Running autoupdate is advised.
1523 AC_DECL_SYS_SIGLIST.
1525 - AC_DEFINE/AC_DEFINE_UNQUOTED
1527 We have to stop using the old compatibility scheme --that tried to
1528 avoid useless backslashes-- because Libtool 1.4.3 contains a
1530 AC_DEFINE([error_t], [int],
1531 [Define to a type to use for \`error_t' if it is not
1532 otherwise available.])
1534 We have to quote the single quotes and backslashes with \. The old
1535 compatibility scheme saw that ` was backslashed, and therefore did
1536 not quote the single quote... Failure. Hence, Autoconf 2.54 is not
1537 compatible with Libtool. Autoconf 2.55 is, but in some cases might
1538 produce more \ than wanted.
1540 Please, note that in the future the same problem will happen with
1541 AC_MSG_*: use `autoreconf -f -Wall'.
1545 - Portability of the Autoconf package to Solaris.
1547 - Spurious warnings caused by config.status.
1548 This bug is benign, but painful: on some systems (typically
1549 FreeBSD), warnings such as:
1551 config.status: creating Makefile
1552 mv: Makefile: set owner/group (was: 1357/0): Operation not permitted
1554 could be issued. This is fixed.
1557 Simultaneous executions of config.status are possible again.
1559 - Precious variables accumulation
1561 config.status could stack several copies of the precious variables
1565 ** Plans for later versions
1567 - ./configure <host>
1569 The compatibility hooks with the old scheme will be completely
1570 removed. Please, advice/use `--build', `--host', and `--target'
1573 - AC_CHECK_HEADER, AC_CHECK_HEADERS
1575 The tests will be stricter, please make sure your invocations are
1580 Shell functions will gradually be introduced, probably starting with
1581 Autotest. If you know machines which are in use that you suspect
1582 *not* to support shell functions, please run the test suite of
1583 Autoconf 2.55 on it, and report the results to
1584 bug-autoconf@gnu.org.
1588 Special characters in AC_MSG_* need not be quoted. Currently,
1589 Autoconf has heuristics to decide when a string is escaped, or has
1590 to be escaped. This scheme is fragile, and will be removed; the
1591 only risk is uglified messages. Please, run `autoreconf -f -Wall'
1592 to find occurrences that will be affected.
1594 * Major changes in Autoconf 2.54
1596 Released 2002-09-13 by Akim Demaille.
1600 - autoreconf no longer changes the version of the gettext/po/intl
1601 support files. It now adds the files the correspond to the
1602 AM_GNU_GETTEXT_VERSION declared in configure.ac.
1604 Warning: It now relies on the 'autopoint' program, which is part
1605 of GNU gettext 0.11.4 and newer.
1607 Please note that you need to have a GNU gettext version that
1608 corresponds at least to the AM_GNU_GETTEXT_VERSION declared
1609 in configure.ac. You can upgrade to newer GNU gettext versions,
1610 though, without needing to change configure.ac.
1612 - The -I DIR or --include=DIR option now appends DIR to the include path
1613 instead of prepending; this is for consistency with other GNU tools.
1614 The new -B DIR or --prepend-include=DIR option has the old behavior.
1619 Now handles all the gory details about LIBOBJS and LTLIBOBJS.
1620 Please, remove lines such as
1622 # This is necessary so that .o files in LIBOBJS are also
1623 # built via the ANSI2KNR-filtering rules.
1624 LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
1626 and read the `AC_LIBOBJ vs LIBOBJS' section. Do not define U in
1627 your Makefiles either.
1629 - AC_CONFIG_LINKS now makes copies if it can't make links.
1631 - AC_FUNC_FNMATCH now tests only for POSIX compatibility, reverting to
1632 Autoconf 2.13 behavior. The new macro AC_FUNC_FNMATCH_GNU also
1633 tests for GNU extensions to fnmatch, and replaces fnmatch if needed.
1635 - AC_FUNC_SETVBUF_REVERSED no longer fails when cross-compiling.
1637 - AC_PROG_CC_STDC is integrated into AC_PROG_CC.
1639 - AC_PROG_F77 default search no longer includes cf77 and cfg77.
1643 AC_C_BACKSLASH_A, AC_CONFIG_LIBOBJ_DIR, AC_GNU_SOURCE,
1644 AC_PROG_EGREP, AC_PROG_FGREP, AC_REPLACE_FNMATCH,
1645 AC_FUNC_FNMATCH_GNU, AC_FUNC_REALLOC, AC_TYPE_MBSTATE_T.
1647 - AC_FUNC_GETLOADAVG
1648 looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
1651 Now defines HAVE_MALLOC to 0 if `malloc' does not work, and asks
1652 for an AC_LIBOBJ replacement.
1656 - Spurious complaints from `m4_bmatch' about invalid regular
1657 expressions are suppressed.
1659 - Empty top_builddirs are properly handled.
1661 - AC_CHECK_MEMBER works correctly when the member is an aggregate.
1664 Now colon in the optional path arguments are properly handled.
1666 ** Improved portability
1668 - Both Autoconf the package, and the scripts it produces, should run
1669 more reliably with Zsh. Bear in mind it is the default Bourne shell
1672 - Autoconf and the scripts it produces no longer assume the existence of
1673 the obsolescent commands egrep and fgrep.
1677 - Limitations of Make
1681 The GNATS base moved to
1682 https://bugs.gnu.org/cgi-bin/gnatsweb.pl?database=autoconf
1683 (It is no longer available, though.)
1688 Now contains the list of output variables and files (AC_SUBST,
1691 * Major changes in Autoconf 2.53
1693 Released 2002-03-08 by Akim Demaille.
1697 Perl 5.005_03 or later is required: autom4te is written in Perl and is
1698 needed by autoconf. autoheader, autoreconf, ifnames, and autoscan are
1704 Argument requirements, output variables, defined macros.
1705 - M4sugar, M4sh, Autotest
1707 - Double quoting macros
1708 AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
1710 The Autoconf manual is now distributed under the terms of the GNU FDL.
1711 - Section `Hosts and Cross-Compilation'
1712 Explains the rationale for the 2.5x changes in the cross-compilation
1713 chain, and in the relationships between build, host, and target
1715 Emphasizes that `cross-compilation' == `--host is given'.
1716 If you are working on compilers etc., be sure to read this section.
1717 - Section `AC_LIBOBJ vs. LIBOBJS'
1718 Explains why assigning LIBOBJS directly is now an error.
1719 Details how to update the code.
1724 Now used instead of hard coded line numbers.
1725 This eases the comparison of `configure's, and diminishes the
1726 pressure over control version archives.
1727 Automatic replacement for shells that don't support this feature.
1728 - New output variables
1729 @builddir@, @top_builddir@, @abs_srcdir@, @abs_top_srcdir@, @abs_builddir@,
1734 Autoconf and Autotest modes are provided.
1739 New, used by the Autoconf suite to cache and speed up most processing.
1741 Supported by autom4te, autoconf and autoheader.
1743 Replaces --autoconf-dir and --localdir in autoconf, autoheader,
1744 autoupdate, and autoreconf.
1746 No longer passes --cygnus, --foreign, --gnits, --gnu, --include-deps:
1747 automake options are to be given via AUTOMAKE_OPTIONS.
1749 Runs gettextize and libtoolize when appropriate.
1751 --m4dir is no longer supported.
1753 Now runs only in the specified directories, defaulting to `.',
1754 but understands AC_CONFIG_SUBDIRS for dependent directories.
1755 Before, it used to run on all the `configure.ac' found in the
1757 Independent packages are properly updated.
1761 - The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
1763 Under the user pressure, $? is finally available. Probably a mistake.
1764 - AC_F77_LIBRARY_LDFLAGS now supports the HP/UX f90 compiler.
1765 - Precious variables accumulation
1766 config.status could stack several copies of the precious variables
1768 - AC_PATH_PROG and family.
1769 Works properly when given a literal path.
1771 Somewhere since 2.13, the result had been reversed.
1775 - AC_C_BIGENDIAN supports the cross-compiling case.
1776 - AC_C_BIGENDIAN accepts ACTION-IF-TRUE, ACTION-IF-FALSE, and
1777 ACTION-IF-UNKNOWN arguments. All are optional, and the default
1778 for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
1780 - AC_C_LONG_DOUBLE now succeeds only if `long double' has more range or
1781 precision than `double'.
1786 It now defines the preprocessor symbols PACKAGE_NAME,
1787 PACKAGE_TARNAME, PACKAGE_VERSION, PACKAGE_STRING, and
1791 Admits a fourth optional parameter: the tar name.
1793 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS.
1794 Provide the user with srcdir, ac_srcdir, ac_top_srcdir, ac_builddir,
1795 ac_top_builddir, ac_abs_srcdir, ac_abs_top_srcdir, ac_abs_builddir,
1796 ac_abs_top_builddir.
1798 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS and AC_OUTPUT.
1799 Are much less expensive when using long lists of files.
1802 Works with shell variables, and non alphanumeric names.
1806 - AC_FUNC_STRERROR_R now sets STRERROR_R_CHAR_P, not HAVE_WORKING_STRERROR_R,
1807 because POSIX 1003.1-200x draft 7 says strerror_r returns int, not char *.
1809 - AC_FUNC_STRTOD substitutes POW_LIB.
1814 * Major changes in Autoconf 2.52
1816 Released 2001-07-18 by Akim Demaille.
1821 This feature was present in autoconf 2.50 but was not documented.
1822 For example, `@<:@' is translated to `[' just before output. This
1823 is useful when writing strings that contain unbalanced quotes, or
1824 other hard-to-quote constructs.
1825 - m4_pattern_forbid, m4_pattern_allow
1826 - Tips for upgrading from 2.13.
1827 - Using autoscan to maintain a configure.ac.
1830 - Now include stdint.h.
1831 - sys/types.h and sys/stat.h are guarded.
1832 - strings.h is included if available, and not conflicting with string.h.
1835 - The test suite is more robust and presents less false failures.
1836 - Invocation of GNU M4 now robust to POSIXLY_CORRECT.
1837 - configure accepts --prefix='' again.
1838 - AC_CHECK_LIB works properly when its first argument is not a
1840 - HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
1841 - build_, host_, and target_alias are AC_SUBST as in 2.13.
1842 - AC_ARG_VAR properly propagates precious variables inherited from the
1843 environment to ./config.status.
1844 - Using --program-suffix/--program-prefix is portable.
1845 - Failures to detect the default compiler's output extension are less
1847 - `config.status foo' works properly when `foo' depends on variables
1848 set in an AC_CONFIG_THING INIT-CMD.
1849 - autoheader is more robust to broken input.
1850 - Fixed Fortran name-mangling and link tests on a number of systems,
1851 e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
1854 - AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
1855 specify pre-includes. In this case, the headers are compiled with
1856 cc, not merely preprocessed by cpp. Therefore it is the _usability_
1857 of a header which is checked for, not just its availability.
1858 - AC_ARG_VAR refuses to run configure when precious variables have
1860 - Versions of compilers are dumped in the logs.
1861 - AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
1864 - AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
1865 - AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
1866 - AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
1867 AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
1868 Be sure to read `Upgrading from Version 2.13' to understand why
1869 running `autoupdate' is needed.
1870 - AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
1871 a main-like routine is required/possible when linking C/C++ with
1872 Fortran. Users of e.g. AC_F77_WRAPPERS should be aware of these.
1873 - AC_FUNC_GETPGRG behaves better when cross-compiling.
1875 * Major changes in Autoconf 2.51
1876 There was no release of Autoconf 2.51 since some packagers had used
1877 this version number without permission to ship intermediary versions
1878 of 2.50. The version was skipped to avoid confusion.
1880 * Major changes in Autoconf 2.50
1882 Released 2001-05-21 by Akim Demaille.
1884 ** Lots of bug fixes
1885 There have been far too many to enumerate them here. Check out
1886 ChangeLog if you really want to know more.
1888 ** Improved documentation
1889 In particular, portability issues are better covered.
1892 All the standard GNU Makefile targets are supported. The layout has
1893 changed: m4/ holds the M4 extensions Autoconf needs for its
1894 configuration, doc/ contains the documentation, and tests/ contains
1897 ** Man pages are provided
1898 For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
1899 config.guess, config.sub.
1903 Provides a safe and powerful means to trace the macro uses. This
1904 provide the parsing layer for tools which need to `study'
1908 Specify what category of warnings should be enabled.
1910 - When recursing into subdirectories, try for configure.gnu before
1911 configure to adapt for packages not using autoconf on case-insensitive
1915 More errors are now caught (circular AC_REQUIRE dependencies,
1916 AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
1917 etc.). In addition, their location and call stack are given.
1920 autoupdate is much more powerful, and is able to provide the glue code
1921 which might be needed to move from an old macro to its newer
1924 You are strongly encouraged to use it to modernize both your
1925 `configure.in' and your .m4 extension files.
1928 The internal machinery of autoheader has completely changed. As a
1929 result, using `acconfig.h' should be considered to be obsoleted, and
1930 you are encouraged to get rid of it using the AH macros.
1935 ** Fortran 77 compilers
1936 Globally, the support for Fortran 77 is considerably improved.
1938 Support for automatically determining a Fortran 77 compiler's
1939 name-mangling scheme. New CPP macros F77_FUNC and F77_FUNC_ are
1940 provided to wrap C/C++ identifiers, thus making it easier and more
1941 transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
1942 call C/C++ routines. See the Texinfo documentation for details.
1945 The test suite no longer uses DejaGNU. It should be easy to submit
1946 test cases in this new framework.
1949 - --help, --help=long, -hl
1950 no longer dumps useless items.
1952 lists only specific options.
1953 - --help=recursive, -hr
1954 displays the help of all the embedded packages.
1955 - Remembers environment variables when reconfiguring.
1956 The previous scheme to set envvar before running configure was
1958 what prevented configure from remembering the environment in which
1959 it was run, therefore --recheck was run in an inconsistent
1960 environment. Now, one should run
1962 and then --recheck will work properly. Variables declared with
1963 AC_ARG_VAR are also preserved.
1965 $build defaults to `config.guess`, $host to $build, and then $target
1967 Cross-compilation is a global status of the package, it no longer
1968 depends upon the current language.
1969 Cross compilation is enabled iff the user specified `--host'.
1970 `configure' now fails if it can't run the executables it compiles,
1971 unless cross-compilation is enabled.
1973 The cache file is disabled by default. The new options
1974 `--config-cache', `-C' set the cache to `config.cache'.
1978 Much faster on most architectures.
1979 - concurrent executions
1980 It is safe to use `make -j' with config.status.
1981 - human interface improved
1982 It is possible to invoke
1983 ./config.status foobar
1984 instead of the former form (still valid)
1985 CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
1986 CONFIG_FILES=foobar:foo.in:bar.in \
1988 The same holds for configuration headers and links.
1989 You can instantiate unknown files and headers:
1990 ./config.status --header foo.h:foo.h.in --file bar:baz
1991 - has a useful --help
1992 - accepts special file name "-" for stdin/stdout
1997 Specify additional copyright information.
2000 Now expects the identity of the package as argument.
2004 Most macros, if not all, now strictly follow the `one quotation
2005 level' rule. This results in a more predictable expansion.
2008 A sly bug in the AC_REQUIRE machinery, which could produce incorrect
2009 configure scripts, was fixed by Axel Thimm.
2013 Document and ask for the registration of an envvar.
2016 Specifies the file which `configure' should look for when trying to
2017 find the source tree (used to be handled by AC_INIT).
2019 - AC_CONFIG_COMMANDS
2020 To add new actions to config.status. Should be used instead of
2024 Replaces AC_LINK_FILES.
2026 - AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
2027 AC_CONFIG_LINKS, and AC_CONFIG_FILES
2028 They now obey sh: you should no longer use shell variables as
2029 argument. Instead of
2031 test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
2032 AC_CONFIG_SUBDIRS($my_subdirs)
2036 if test "$package_foo_enabled" = yes; then
2037 AC_CONFIG_SUBDIRS(foo)
2041 To format an Autoconf macro's help string so that it looks pretty
2042 when the user executes `configure --help'.
2045 ** Generic Test Macros
2047 The interface of the AC_CHECK families of macros (decl, header,
2048 type, member, func) is now uniform. They support the same set of
2051 - AC_CHECK_DECL, AC_CHECK_DECLS
2052 To check whether a symbol is declared.
2054 - AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
2055 No longer need a cross-compilation default.
2058 The test it performs is much more robust than previously, and makes
2059 it possible to test builtin types in addition to typedefs.
2060 It is now schizophrenic:
2061 - AC_CHECK_TYPE(TYPE, REPLACEMENT)
2062 remains for backward compatibility, but its use is discouraged.
2063 - AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
2064 behaves exactly like the other AC_CHECK macros.
2067 Checks whether given types are supported by the system.
2069 - AC_CHECK_MEMBER, AC_CHECK_MEMBERS
2070 Check for given members in aggregates (e.g., pw_gecos in struct
2074 Checks if the compiler supports ISO C, included when needs special
2078 Checking whether the preprocessor indicates missing includes by the
2079 error code. stderr is checked by AC_TRY_CPP only as a fallback.
2082 Takes a language as argument and replaces AC_LANG_C,
2083 AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
2085 - AC_LANG_PUSH, AC_LANG_POP
2086 Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
2089 - AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
2090 AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
2091 AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
2095 Sets GETGROUPS_LIBS.
2097 - AC_FUNC_GETLOADAVG
2098 Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
2101 Now integrates `AC_DECL_YYTEXT' which is obsoleted.
2104 Arrange for large-file support.
2106 - AC_EXEEXT, AC_OBJEXT
2107 You are no longer expected to use them: their computation is
2108 performed by default.
2110 ** C++ compatibility
2111 Every macro has been revisited in order to support at best CC=c++.
2113 Major changes in Autoconf 2.14:
2114 There was no release of GNU Autoconf 2.14.
2116 Major changes in Autoconf 2.13:
2118 Released 1999-05-01 by Ben Elliston.
2120 * Support for building on 32-bit Windows systems where the only available C or
2121 C++ compiler is the Microsoft Visual C++ command line compiler
2122 (`cl'). Additional support for building on 32-bit Windows systems which are
2123 using the Cygwin or Mingw32 environments.
2124 * Support for alternative object file and executable file extensions.
2125 On 32-bit Windows, for example, these are .obj and .exe. These are discovered
2126 using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
2127 @EXEEXT@ in the output, respectively.
2128 * New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
2129 AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
2130 AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
2131 * AC_DEFINE now has an optional third argument for a description to be
2132 placed in the config header input file (e.g. config.h.in).
2133 * The C++ code fragment compiled for the C++ compiler test had to be
2134 improved to include an explicit return type for main(). This was
2135 causing failures on systems using recent versions of the EGCS C++
2137 * Fixed an important bug in AC_CHECK_TYPE that would cause a configure
2138 script to report that `sometype_t' was present when only `type_t'
2140 * Merge of the FSF version of config.guess and config.sub to modernize
2141 these scripts. Add support for a few new hosts in config.guess.
2142 Incorporate latest versions of install-sh, mkinstalldirs and
2143 texinfo.tex from the FSF.
2144 * autoreconf is capable of running automake if necessary (and
2146 * Support for Fortran 77. See the Texinfo documentation for details.
2147 * Bug fixes and workarounds for quirky bugs in vendor utilities.
2149 Major changes in Autoconf 2.12:
2151 Released 1996-11-26 by David J. MacKenzie
2153 * AC_OUTPUT and AC_CONFIG_HEADERS can create output files by
2154 concatenating multiple input files separated by colons, like so:
2155 AC_CONFIG_HEADERS([config.h:conf.pre:config.h.in:conf.post])
2156 AC_OUTPUT([Makefile:Makefile.in:Makefile.rules])
2157 The arguments may be shell variables, to compute the lists on the fly.
2158 * AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
2159 * New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
2162 Major changes in Autoconf 2.11:
2164 Released November 18th, 1996, by David J. MacKenzie
2166 * AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
2167 They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
2168 * AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
2169 * AC_CONFIG_HEADERS expands shell variables in its argument.
2170 * New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
2171 * The "checking..." messages and the source code for test programs that
2172 fail are saved in config.log.
2173 * Another workaround has been added for seds with small command length limits.
2174 * config.sub and config.guess recognize more system types.
2177 Major changes in Autoconf 2.10:
2179 Released May 7th, 1996, by Roland McGrath
2182 * The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
2183 changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
2185 Major changes in Autoconf 2.9:
2187 Released March 16th, 1996, by Roland McGrath
2191 Major changes in Autoconf 2.8:
2193 Released March 8th, 1996, by Roland McGrath
2197 Major changes in Autoconf 2.7:
2199 Released November 22nd, 1995, by David J. MacKenzie
2203 Major changes in Autoconf 2.6:
2205 Released November 20th, 1995, by David J. MacKenzie
2209 Major changes in Autoconf 2.5:
2211 Released November 17th, 1995, by Roland McGrath
2213 * New configure options --bindir, --libdir, --datadir, etc., with
2214 corresponding output variables.
2215 * New macro: AC_CACHE_CHECK, to make using the cache easier.
2216 * config.log contains the command being run as well as any output from it.
2217 * AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
2218 * AC_PROG_INSTALL doesn't cache a name for install-sh, for sharing caches.
2219 * AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
2220 AC_CHECK_TOOL can search a path other than $PATH.
2221 * AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
2223 Major changes in Autoconf 2.4:
2225 Released June 14th, 1995, by David J. MacKenzie
2227 * Fix a few bugs found by Emacs testers.
2229 Major changes in Autoconf 2.3:
2231 Released March 27th, 1995, by David J. MacKenzie
2233 * Fix the cleanup trap in several ways.
2234 * Handle C compilers that are picky about option placement.
2235 * ifnames gets the version number from the right directory.
2237 Major changes in Autoconf 2.2:
2239 Released March 8th, 1995, by David J. MacKenzie
2241 * The ifnames utility is much faster but requires a "new awk" interpreter.
2242 * AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
2243 library before existing libs, not after, in case it uses them.
2244 * New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
2245 * Lots of bug fixes.
2246 * Many additions to the TODO file :-)
2248 Major changes in Autoconf 2.1:
2250 Released November 4th, 1994, by David J. MacKenzie
2253 * More explanations in the manual.
2254 * Fix a spurious failure in the testsuite.
2255 * Clarify some warning messages.
2256 * autoreconf by default only rebuilds configure and config.h.in files
2257 that are older than any of their particular input files; there is a
2258 --force option to use after installing a new version of Autoconf.
2260 Thanks to everybody who's submitted changes and additions to Autoconf!
2261 I've incorporated many of them, and am still considering others for
2262 future releases -- but I didn't want to postpone this release indefinitely.
2264 Caution: don't indiscriminately rebuild configure scripts with
2265 Autoconf version 2. Some configure.in files need minor adjustments to
2266 work with it; the documentation has a chapter on upgrading. A few
2267 configure.in files, including those for GNU Emacs and the GNU C
2268 Library, need major changes because they relied on undocumented
2269 internals of version 1. Future releases of those packages will have
2270 updated configure.in files.
2272 It's best to use GNU M4 1.3 (or later) with Autoconf version 2.
2273 Autoconf now makes heavy use of M4 diversions, which were implemented
2274 inefficiently in GNU M4 releases before 1.3.
2276 Major changes in Autoconf 2.0:
2278 Released October 26th, 1994, by David J. MacKenzie
2280 ** New copyright terms:
2281 * There are no restrictions on distribution or use of configure scripts.
2284 * Autoconf manual is reorganized to make information easier to find
2285 and has several new indexes.
2286 * INSTALL is reorganized and clearer and is now made from Texinfo source.
2289 * autoscan to generate a preliminary configure.in for a package by
2290 scanning its source code for commonly used nonportable functions,
2291 programs, and header files.
2292 * ifnames to list the symbols used in #if and #ifdef directives in a
2294 * autoupdate to update a configure.in to use the version 2 macro names.
2295 * autoreconf to recursively remake configure and configuration header
2296 files in a source tree.
2298 ** Changed utilities:
2299 * autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
2300 * autoconf and autoheader can look for package-local definition files
2301 in an alternate directory.
2304 * AC_CACHE_VAL to share results of tests between configure runs.
2305 * AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
2306 that macros invoked with AC_REQUIRE don't interrupt other macros.
2307 * AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
2308 support deciding unguessable features based on the host and target types.
2309 * AC_CONFIG_SUBDIRS to recursively configure a source tree.
2310 * AC_ARG_PROGRAM to use the options --program-prefix,
2311 --program-suffix, and --program-transform-name to change the names
2312 of programs being installed.
2313 * AC_PREFIX_DEFAULT to change the default installation prefix.
2314 * AC_TRY_COMPILE to compile a test program without linking it.
2315 * AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
2316 * AC_CHECK_LIB to check for a particular function and library.
2317 * AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
2318 whether or not the test succeeds. They obsolete AC_CHECKING and AC_VERBOSE.
2319 * AC_SUBST_FILE to insert one file into another.
2320 * AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
2321 * AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
2322 * AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
2323 * AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
2326 * Many macros renamed systematically, but old names are accepted for
2327 backward compatibility.
2328 * AC_OUTPUT adds the "automatically generated" comment to
2329 non-Makefiles where it finds @configure_input@ in an input file, to
2330 support files with various comment syntaxes.
2331 * AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
2332 files when they are not enclosed in @ signs.
2333 * AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
2334 override the file name "config.status".
2335 * AC_OUTPUT takes an optional argument for passing variables from
2336 configure to config.status.
2337 * AC_OUTPUT and AC_CONFIG_HEADERS allow you to override the input-file names.
2338 * AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
2339 CPPFLAGS, and LDFLAGS from the environment.
2340 * AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
2341 * AC_PROG_INSTALL looks for install-sh or install.sh in the directory
2342 specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
2343 srcdir/../.. by default.
2344 * AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
2345 * AC_DEFINE no longer prints anything, because of the new result reporting
2346 mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
2347 * AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
2348 * AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
2349 --enable- and --with- options.
2350 * AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
2351 execute on success or failure.
2352 * Checking for C functions in C++ works.
2355 * AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
2356 better maintained with them.
2357 * AC_ARG_ARRAY removed because no one was likely using it.
2358 * AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
2359 take arguments, for consistency with all of the other specific checks.
2362 * Comes with config.sub and config.guess, and uses them optionally.
2363 * Uses config.cache to cache test results. An alternate cache file
2364 can be selected with the --cache-file=FILE option.
2365 * Uses optional shell scripts $prefix/share/config.site and
2366 $prefix/etc/config.site to perform site or system specific initializations.
2367 * configure saves compiler output to ./config.log for debugging.
2368 * New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
2369 * acsite.m4 is the new name for the system-wide aclocal.m4.
2370 * Has a DejaGnu test suite.
2372 Major changes in Autoconf 1.11:
2374 * AC_PROG_INSTALL calls install.sh with the -c option.
2375 * AC_SET_MAKE cleans up after itself.
2376 * AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
2377 * AC_OUTPUT prevents shells from looking in PATH for config.status.
2379 Plus a few other bug fixes.
2381 Major changes in Autoconf 1.10:
2383 * autoheader uses config.h.bot if present, analogous to config.h.top.
2384 * AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
2386 * AC_PROG_CXX looks for cxx as a C++ compiler.
2388 Plus several bugs fixed.
2390 Major changes in Autoconf 1.9:
2392 * AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
2393 * AC_SIZEOF_TYPE generates the cpp symbol name automatically,
2394 and autoheader generates entries for those names automatically.
2395 * AC_FIND_X gets the result from xmkmf correctly.
2396 * AC_FIND_X assumes no X if --without-x was given.
2397 * AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
2398 * AC_PROG_INSTALL finds OSF/1 installbsd.
2400 Major changes in Autoconf 1.8:
2403 * New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
2404 AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
2405 for checking both C++ and C features in one configure script.
2406 * New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
2407 * New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
2408 AC_SET_MAKE, AC_ENABLE.
2411 * AC_FIND_X looks for X in more places.
2412 * AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
2413 install.sh is distributed with Autoconf.
2414 * AC_DECLARE_YYTEXT has been removed because it can't work, pending
2415 a rewrite of quoting in AC_DEFINE.
2416 * AC_OUTPUT adds its comments in C format when substituting in C files.
2417 * AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
2419 ** New or changed command line options:
2420 * configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
2421 * configure accepts --without-PACKAGE, which sets withval=no.
2422 * configure accepts --x-includes=DIR and --x-libraries=DIR.
2423 * Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
2424 * configure accepts --help, --version, --silent/--quiet, --no-create options.
2425 * configure accepts and ignores most other Cygnus configure options, and
2426 warns about unknown options.
2427 * config.status accepts --help, --version options.
2429 ** File names and other changes:
2430 * Relative srcdir values are not made absolute.
2431 * The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
2432 * Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
2433 * autoheader optionally copies config.h.top to the beginning of config.h.in.
2434 * The example Makefile dependencies for configure et al. work better.
2435 * Namespace cleanup: all shell variables used internally by Autoconf
2436 have names beginning with `ac_'.
2438 More big improvements are in process for future releases, but have not
2439 yet been (variously) finished, integrated, tested, or documented enough
2442 Major changes in Autoconf 1.7:
2444 * New macro AC_OBSOLETE.
2445 * Bugs in Makefile.in fixed.
2446 * AC_LONG_FILE_NAMES improved.
2448 Major changes in Autoconf 1.6:
2450 * New macro AC_LONG_64_BITS.
2451 * Multiple .h files can be created.
2452 * AC_FIND_X looks for X files directly if it doesn't find xmkmf.
2453 * AC_ALLOCA defines C_ALLOCA if using alloca.c.
2454 * --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
2455 * Unused --no-create option to configure removed.
2456 * autoheader doesn't change the timestamp of its output file if
2457 the file didn't change.
2458 * All macros that look for libraries now use AC_HAVE_LIBRARY.
2459 * config.status checks three optional environment variables to
2460 modify its behavior.
2461 * The usual bug fixes.
2463 Major changes in Autoconf 1.5:
2465 * New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
2466 * autoconf and autoheader scripts have GNU standards conforming
2467 --version and --help options (they print their message and exit).
2470 Major changes in Autoconf 1.4:
2472 * New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
2473 AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
2474 * autoconf and autoheader use the M4 environment variable to determine the
2475 name of the M4 program to use.
2476 * The --macrodir option to autoconf and autoheader specifies the directory
2477 in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
2478 * autoconf and autoheader can take `-' as their file names, which means to
2479 read stdin as input.
2480 * Resulting configure scripts can take a --verbose option which causes them
2481 to print the results of their tests.
2482 * AC_DEFINE quotes its second argument in such a way that spaces, magic
2483 shell characters, etc. will be preserved during various stages of
2484 expansion done by the shell. If you don't want this, use
2485 AC_DEFINE_UNQUOTED instead.
2486 * Much textual processing done with external calls to tr and sed have been
2487 internalized with builtin M4 `patsubst' and `translit' calls.
2488 * AC_OUTPUT doesn't hardwire the file names it outputs. Instead, you can
2489 set the shell variables `gen_files' and `gen_config' to the list of
2490 file names to output.
2491 * AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
2492 "lex.yy" or "lexyy", depending on the system.
2493 * AC_PROGRAMS_CHECK takes an optional third arg. If given, it is used as
2495 * If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
2496 * AC_CONST works much more reliably on more systems.
2499 Major changes in Autoconf 1.3:
2501 configure no longer requires awk for packages that use a config.h.
2502 Support handling --with-PACKAGE options.
2503 New `autoheader' script to create `config.h.in' from `configure.in'.
2504 Ignore troublesome -lucb and -lPW when searching for alloca.
2505 Rename --exec_prefix to --exec-prefix for GNU standards conformance.
2506 Improve detection of STDC library.
2507 Add AC_HAVE_LIBRARY to check for non-default libraries.
2508 Function checking should work with future GNU libc releases.
2510 Major changes in Autoconf 1.2:
2512 The --srcdir option is now usually unnecessary.
2513 Add a file containing sample comments describing CPP macros.
2514 A comment in config.status tells which host it was configured on.
2515 Substituted variable values can now contain commas.
2516 Fix bugs in various feature checks.
2518 Major changes in Autoconf 1.1:
2520 Added AC_STRCOLL macro.
2521 Made AC_GETLOADAVG check for more things.
2522 AC_OUTPUT argument is now optional.
2527 Copyright (C) 1993-1996, 1998-2017, 2020 Free Software Foundation, Inc.
2529 Copying and distribution of this file, with or without modification,
2530 are permitted in any medium without royalty provided the copyright
2531 notice and this notice are preserved. This file is offered as-is,
2532 without warranty of any kind.