1 GNU Autoconf NEWS - User visible changes.
3 * Noteworthy changes in release ?.? (????-??-??) [?]
5 ** Configure scripts now support a '--runstatedir' option, which
6 defaults to '${localstatedir}/run', and which can be used to place
7 per-process temporary runtime files (such as pid files) into '/run'
10 ** The use of the long-deprecated name 'configure.in' for the autoconf
11 input file now elicits a warning in the 'obsolete' category.
13 ** Older version of automake and aclocal (< 1.8) are no longer supported
16 ** Use of printf is now recommended instead of working around bugs in
17 echo. Macros AS_ECHO and AS_ECHO_N now expand unconditionally to
18 'printf "%s\n"' and 'printf %s'.
20 ** AC_CHECK_HEADER and AC_CHECK_HEADERS now default to doing only a
21 compilation test. This completes the transition from preprocessor-
22 based header tests begun in Autoconf 2.56.
24 The double test that was the default since Autoconf 2.64 is no
25 longer available. You can still request a preprocessor-only test
26 by specifying '-' as the fourth argument to either macro, but this
27 is now deprecated. If you really need that behavior use
32 - New macro AC_C__GENERIC.
34 - AC_C_VARARRAYS now defines __STDC_NO_VLA__ if variable-length
35 arrays are not supported and if the compiler does not already
36 define __STDC_NO_VLA__. This is for compatibility with C11.
37 For backward compatibility with Autoconf 2.61-2.69 AC_C_VARARRAYS
38 still defines HAVE_C_VARARRAYS, but this usage is obsolescent.
40 - AC_CONFIG_MACRO_DIRS
41 New macro, used to declare multiple directories when looking for
42 local M4 macros. This macro overcomes some of the shortfalls in the
43 older AC_CONFIG_MACRO_DIR, which could only be used once; although
44 the older macro remains for compatibility with older tools. The
45 newer macro will be used by the upcoming Automake 1.13 release to
46 eliminate the need to specify ACLOCAL_AMFLAGS in Makefile.am.
48 - AC_PROG_CC now prefers C11 if available, falling back on C99 and
49 then on C89 as before. Similarly, AC_PROG_CXX now prefers C++11
50 if available, falling back on C++98.
52 - AC_PROG_CC is now defined via AC_DEFUN_ONCE, to avoid bloat in 'configure'.
54 - AC_PROG_CC_STDC, AC_PROG_CC_C89, AC_PROG_CC_C99 have been marked as obsolete.
55 Applications should use AC_PROG_CC.
57 - AC_PROG_YACC now uses 'bison -o y.tab.c' instead of 'bison -y', so that
58 by default it no longer warns about Bison extensions. Add -Wyacc to
59 YFLAGS to enable these warnings.
61 - AC_USE_SYSTEM_EXTENSIONS now enables more system extensions on HP-UX,
64 - AC_FUNC_VFORK now checks for the signal-handling bug in Solaris 2.4 'vfork'.
65 Formerly, it ignored this bug, so that Emacs could use some tricky
66 code on that platform. Solaris 2.4 has not been supported since
67 2003 and nowadays it's better to omit that old trick.
69 - Autotest provides a new macro AT_DATA_UNQUOTED, similar to AT_DATA
70 but processing variable substitutions, command substitutions and
71 backslashes in the contents argument.
73 - AC_CONFIG_TESTDIR will automatically pass EXEEXT to a testsuite (via
76 - AT_TESTED arguments can use variable or command substitutions, including
79 - AC_INCLUDES_DEFAULT has been streamlined. It now assumes that the
80 ISO C90 headers 'stdlib.h' and 'string.h' are unconditionally
81 available, and does not include the pre-standard header 'memory.h'
82 at all. If the POSIX header 'strings.h' exists, it will be
83 included; it is assumed to be safe to include both 'string.h' and
84 'strings.h' in the same source file. We are not aware of any
85 current system that violates any of the above assumptions.
87 For compatibility's sake, the C preprocessor macros STDC_HEADERS,
88 HAVE_STDLIB_H, and HAVE_STRING_H are defined unconditionally.
89 These preprocessor macros should be considered obsolescent.
91 Future releases of Autoconf may reduce the set of headers checked
92 for by AC_INCLUDES_DEFAULT.
94 - AC_HEADER_STDC and AC_HEADER_TIME are now stubs which will be
95 removed from 'configure.ac' by 'autoupdate'. For compatibility's
96 sake, the stubs (and their 'autoupdate' replacements) continue to
97 define the C preprocessor macros STDC_HEADERS and TIME_WITH_SYS_TIME,
98 respectively, but without actually checking for the ancient systems
99 where formerly those macros would not be defined.
101 These macros were already labeled obsolescent in the manual.
103 - New macro, AC_CHECK_INCLUDES_DEFAULT. It causes the checks normally
104 performed as a side-effect by AC_INCLUDES_DEFAULT to happen at that
105 point in 'configure', if they haven't already been done. Autoupdate
106 will replace certain obsolete constructs, whose only remaining
107 useful effect is to trigger those checks, with this macro. It is
108 unlikely to be useful otherwise.
110 * Noteworthy changes in release 2.69 (2012-04-24) [stable]
112 ** Autoconf now requires perl 5.6 or better (but generated configure
113 scripts continue to run without perl).
115 * Noteworthy changes in release 2.68b (2012-03-01) [beta]
116 Released by Eric Blake, based on git versions 2.68.*.
118 ** Autoconf-generated configure scripts now unconditionally re-execute
119 themselves with $CONFIG_SHELL, if that's set in the environment.
121 ** The texinfo documentation no longer specifies "front-cover" or
122 "back-cover" texts, so that it may now be included in Debian's
125 ** Support for the Go programming language has been added. The new macro
126 AC_LANG_GO sets variables GOC and GOFLAGS.
128 ** AS_LITERAL_IF again treats '=' as a literal. Regression introduced in
131 ** The macro AS_EXECUTABLE_P, present since 2.50, is now documented.
135 - AC_PROG_LN_S and AS_LN_S now fall back on 'cp -pR' (not 'cp -p') if 'ln -s'
136 does not work. This works better for symlinks to directories.
138 - New macro AC_HEADER_CHECK_STDBOOL.
140 - New and updated macros for Fortran support:
142 AC_FC_CHECK_BOUNDS to enable array bounds checking
143 AC_F77_IMPLICIT_NONE and AC_FC_IMPLICIT_NONE to disable implicit integer
144 AC_FC_MODULE_EXTENSION to compute the Fortran 90 module name extension
145 AC_FC_MODULE_FLAG for the Fortran 90 module search path flag
146 AC_FC_MODULE_OUTPUT_FLAG for the Fortran 90 module output directory flag
147 AC_FC_PP_SRCEXT for preprocessed Fortran source files extensions
148 AC_FC_PP_DEFINE for the Fortran preprocessor define flag
150 * Noteworthy changes in release 2.68 (2010-09-22) [stable]
151 Released by Eric Blake, based on git versions 2.67.*.
153 ** AC_MSG_ERROR (and AS_ERROR) can once again be followed immediately by
154 `dnl'. Regression introduced in 2.66.
156 ** AC_INIT again allows URLs with '?' for its BUG-REPORT argument.
157 Regression introduced in 2.66.
159 ** AC_REPLACE_FUNCS again allows a non-literal argument, such as a shell
160 variable that expands to a list of functions to check. Regression
163 ** AT_BANNER() with empty argument will cause visual separation from previous
166 ** The macros AC_PREPROC_IFELSE, AC_COMPILE_IFELSE, AC_LINK_IFELSE, and
167 AC_RUN_IFELSE now warn if the first argument failed to use
168 AC_LANG_SOURCE or AC_LANG_PROGRAM to generate the conftest file
169 contents. A new macro AC_LANG_DEFINES_PROVIDED exists if you have
170 a compelling reason why you cannot use AC_LANG_SOURCE but must
173 ** The macro m4_define_default is now documented.
175 ** Symlinked config.cache files are supported; configure now tries to
176 update non-symlinked cache files atomically, so that concurrent configure
177 runs do not leave behind broken cache files. It is still unspecified
178 which subset or union of results is cached though.
180 ** Autotest testsuites should not contain long text lines any more, and be
181 portable even when very many test groups are used.
183 ** AT_CHECK semantics with respect to the Autotest variable $at_status and
184 shell execution environment of the arguments are documented now.
186 ** AC_FC_LIBRARY_LDFLAGS now tolerates output from newer gfortran.
188 ** Newly obsolete macros
189 The following macros have been marked obsolete. New programs
190 should use the corresponding Gnulib modules. Gnulib not only
191 detects a larger set of portability problems with these functions,
192 but also provides complete workarounds.
194 AC_FUNC_ERROR_AT_LINE AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK
195 AC_FUNC_MKTIME AC_FUNC_STRTOD
198 * Major changes in Autoconf 2.67 (2010-07-21) [stable]
199 Released by Eric Blake, based on git versions 2.66.*.
201 ** AC_CONFIG_SUBDIRS with more than one subdirectory at a time works again.
202 Regression introduced in 2.66.
204 ** AC_CHECK_SIZEOF of a pointer type works again. Regression introduced in
207 ** New macro AC_FC_LINE_LENGTH to accept long Fortran source code lines.
209 ** AC_PREPROC_IFELSE now keeps the preprocessed output in the conftest.i
210 file for inspection by the commands in the ACTION-IF-TRUE argument.
212 ** AC_INIT again allows parentheses and other characters that are literal
213 in single- or double-quoted strings, and in quoted and unquoted
214 here-documents, for its PACKAGE and VERSION arguments. Regression
217 ** autoreconf passes warning flags to new enough versions of aclocal.
219 ** Running an Autotest testsuite in parallel mode no longer triggers a
220 race condition that could cause the testsuite run to end early,
221 fixing a sporadic failure in autoconf's own testsuite. Bug present
222 since introduction of parallel tests in 2.63b.
225 * Major changes in Autoconf 2.66 (2010-07-02) [stable]
226 Released by Eric Blake, based on git versions 2.65.*.
228 ** AC_FUNC_MMAP works in C++ mode again. Regression introduced in 2.65.
230 ** Use of m4_divert without a named diversion now issues a syntax warning,
231 since it is seldom right to change diversions behind autoconf's back.
233 ** The macros AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, and
234 AC_TYPE_INT64_T work again. Regression introduced in 2.65.
236 ** AC_PROG_INSTALL correctly uses `shtool' again. Regression introduced
239 ** Autoconf should work on EBCDIC hosts.
241 ** AC_CHECK_DECL and AC_CHECK_DECLS accept optional function argument types
242 for overloaded C++ functions.
244 ** AS_SET_CATFILE accepts nonliterals in its variable name argument now.
246 ** Autotest testsuites accept an option --recheck to rerun tests that
247 failed or passed unexpectedly during the last non-debug testsuite run.
249 ** AC_ARG_ENABLE and AC_ARG_WITH now also accept `+' signs in `--enable-*'
250 and `--with-*' arguments, converting them to underscores for the variable
253 ** In configure scripts, loading CONFIG_SITE no longer searches PATH,
254 and problems in loading the configuration site files are diagnosed.
256 ** Autotest testsuites may optionally provide colored test results.
258 ** The previously undocumented Autotest macros AT_ARG_OPTION and
259 AT_ARG_OPTION_ARG have seen bug fixes and are documented now.
260 AT_ARG_OPTION has been changed in that the negative of a long option
261 --OPTION is now --no-OPTION rather than --noOPTION.
263 ** The macro AS_LITERAL_IF is slightly more conservative; text
264 containing shell quotes are no longer treated as literals.
265 Furthermore, a new macro, AS_LITERAL_WORD_IF, adds an additional
266 level of checking that no whitespace occurs in literals.
268 ** The macros AS_TR_SH and AS_TR_CPP no longer expand their results.
270 ** The following macros are now documented:
273 ** New macro AC_FC_FIXEDFORM to accept fixed-form Fortran.
276 * Major changes in Autoconf 2.65 (2009-11-21) [stable]
277 Released by Eric Blake, based on git versions 2.64.*.
279 ** Autoconf is now licensed under the General Public License version 3
280 or later (GPLv3+). As with earlier versions, the license includes
281 an exception clause so that you may release a configure script
282 generated by autoconf under the license of your own program.
284 ** New macros to support Objective C++.
285 AC_PROG_OBJCXX AC_PROG_OBJCXXCPP
287 ** The following undocumented autoconf macros, removed in Autoconf 2.64,
288 have been reinstated:
291 These macros are present only for backwards compatibility purposes.
293 ** The macro AC_LANG_COMPILER no longer fails on embedded systems that
294 lack fopen in the C library, such as AVR or RTEMS (regression
297 ** The AC_FC_FREEFORM macro no longer suffers from a whitespace bug that
298 made it fail with some Fortran compilers (regression introduced in
301 ** The AC_TYPE_UINT64_T and AC_TYPE_INT64_T macros have been fixed to no
302 longer mistakenly select a 32-bit type on some compilers (bug present
303 since macros were introduced in 2.59c).
305 ** The AC_FUNC_MMAP macro has been fixed to be portable to systems like
306 Cygwin (bug present since macro was introduced in 2.0).
308 ** The following documented autotest macros are new:
311 ** The following m4sugar macros now quote their expansion:
312 m4_toupper m4_tolower
314 ** The following m4sugar macros are new:
317 ** The m4sugar macro m4_text_wrap now copes with embedded quoting without
318 requiring quadrigraphs. For uses like AC_ARG_VAR([a], [[b c]]),
319 this gives the intuitive behavior of "[b c]" in the output (2.63
320 gave the output of "[b], [c]", and 2.64 encountered a failure).
322 ** The `$tmp' temporary directory used in config.status is documented for
325 ** config.status now provides a --config option to produce the configuration.
327 ** Many cache variables used by Autoconf's macros are now documented.
329 ** Configure scripts work better on DJGPP by avoiding a bug present in
330 the DJGPP port of bash 2.04 in handling 'return' in a shell
331 function (regression introduced in 2.64).
333 * Major changes in Autoconf 2.64 (2009-07-26) [stable]
334 Released by Eric Blake, based on git versions 2.63b.*.
336 ** Autoconf now requires GNU M4 1.4.6 or later. Earlier versions of M4
337 have a bug in regular expression handling that interferes with some
338 of the speedups provided since Autoconf 2.63. GNU M4 1.4.13 or
339 later is recommended.
341 ** AS_IF and AS_CASE have been taught to avoid syntax errors even when
342 given arguments that expand to just whitespace.
344 ** The following documented autoconf macros are new:
345 AC_ERLANG_SUBST_ERTS_VER
347 ** The autoheader tool now understands m4 macro arguments passed to
348 AC_DEFINE and AC_DEFINE_UNQUOTED.
350 ** Ensure AT_CHECK can support commands that include a # given with
351 proper m4 quoting. For shell comments, this is a new feature; for
352 non-shell comments, this fixes a regression introduced in 2.63b.
353 Additionally, AT_CHECK correctly supplies shell escapes for
354 metacharacters occurring in m4 macro expansions within the expected
355 stdout and stderr parameters.
357 ** The macro AT_CHECK now understands the concept of hard failure. If
358 a test exits with an unexpected status 99, cleanup actions for the
359 test are inhibited and the test is treated as a failure regardless
360 of AT_XFAIL_IF. It also understands the new directives
361 ignore-nolog, stdout-nolog, and stderr-nolog.
363 ** The following documented autotest macros are new:
364 AT_CHECK_UNQUOTED AT_FAIL_IF AT_SKIP_IF
366 ** The following documented m4sugar macros are new:
367 m4_argn m4_copy_force m4_default_nblank m4_default_nblank_quoted
368 m4_ifblank m4_ifnblank m4_rename_force
370 ** The autoconf testsuite now exercises all Erlang macros.
372 * Major changes in Autoconf 2.63b (2009-03-31) [beta]
373 Released by Eric Blake, based on git versions 2.63.*.
375 ** The manual is now shipped under the terms of the GNU FDL 1.3.
377 ** AC_REQUIRE now detects the case of an outer macro which first expands
378 then later indirectly requires the same inner macro. Previously,
379 this case led to silent out-of-order expansion (bug present since
380 2.50); it now issues a syntax warning, and duplicates the expansion
381 of the inner macro to guarantee dependencies have been met. See
382 the manual for advice on how to refactor macros in order to avoid
383 the bug in earlier autoconf versions and avoid increased script
384 size in the current version.
386 ** AC_DEFUN_ONCE has improved semantics. Previously, a macro declared
387 with AC_DEFUN_ONCE warned on a second invocation; and out-of-order
388 expansion was still possible. Now, dependencies are guaranteed,
389 and subsequent invocations are a silent no-op. This makes
390 AC_DEFUN_ONCE an ideal macro for silencing AC_REQUIRE warnings.
392 ** The following macros are now defined with AC_DEFUN_ONCE. This means
393 a subtle change in semantics; previously, an AC_DEFUN macro could
394 expand one of these macros multiple times or surround the macro
395 inside shell conditional text to bypass the effects of these
396 macros, but now the macro will expand exactly once, and prior to
397 the start of any enclosing AC_DEFUN macro:
398 AC_CANONICAL_BUILD AC_CANONICAL_HOST AC_CANONICAL_TARGET
399 AC_HEADER_ASSERT AC_PROG_INSTALL AC_PROG_MKDIR_P
400 AC_USE_SYSTEM_EXTENSIONS
402 ** AC_LANG_ERLANG works once again (regression introduced in 2.61a).
404 ** AC_HEADER_ASSERT is fixed so that './configure --enable-assert' no
405 longer mistakenly disables assertions.
407 ** AC_INIT now takes an optional fifth parameter that can be used to
408 set AC_PACKAGE_URL, a URL for the package's home page; the URL is
409 used in `configure --help' and is also available via AC_DEFINE.
411 ** Autotest testsuites accept an option --jobs[=N] for parallel testing.
412 This feature is still in testing, and may not work on every
413 platform, help in improving it would be appreciated.
415 ** Autotest testsuites do not attempt to write startup error messages
416 to the log file before that is opened (regression introduced in 2.63).
418 ** Configure scripts now use shell functions. This feature leads to
419 smaller configure files and faster execution.
421 ** Present But Cannot Be Compiled: Autoconf will now proceed with
422 the compiler's result if a header is present but cannot be compiled.
423 The warning is still printed, and you should really fix it by
424 providing a fourth parameter to AC_CHECK_HEADER/AC_CHECK_HEADERS.
426 ** Autoreconf added aclocal to the set of programs affected by the
427 `autoreconf -I dir' option.
429 ** The following documented m4sugar macros are new:
430 m4_chomp m4_chomp_all m4_cleardivert m4_curry m4_default_quoted
431 m4_esyscmd_s m4_map_args m4_map_args_pair m4_map_args_sep
432 m4_map_args_w m4_set_map m4_set_map_sep m4_stack_foreach
433 m4_stack_foreach_lifo m4_stack_foreach_sep
434 m4_stack_foreach_sep_lifo
436 ** The following m4sugar macros are documented now, but in some cases
437 with slightly different semantics than what the previous
438 undocumented version had:
439 m4_copy m4_dumpdefs m4_rename m4_version_prereq
441 ** The m4sugar macro m4_expand has been taught to handle unterminated
442 comments and shell case statements. As a result, it is used
443 internally in more places, such as AC_DEFINE and AT_CHECK. Most
444 uses of AC_DEFINE and AT_CHECK should not behave any differently;
445 however, it may be necessary to add double-quoting around
446 unbalanced `(' where single-quoting used to be sufficient.
448 ** The following documented m4sh macros are new:
449 AS_INIT_GENERATED AS_LINENO_PREPARE AS_ME_PREPARE AS_SET_STATUS
450 AS_VAR_APPEND AS_VAR_ARITH AS_VAR_COPY
452 ** The following m4sh macros are documented now, but in some cases
453 with slightly different semantics than what the previous
454 undocumented version had:
455 AS_ECHO AS_ECHO_N AS_ESCAPE AS_EXIT AS_LITERAL_IF AS_UNSET
456 AS_VAR_IF AS_VAR_POPDEF AS_VAR_PUSHDEF AS_VAR_SET AS_VAR_SET_IF
457 AS_VAR_TEST_SET AS_VERSION_COMPARE
459 ** The m4sh macros AS_IF and AS_CASE can now be used in shell lists.
460 The responsibility for supplying a trailing newline now belongs to
461 the call site, but since most users did not add dnl, this generally
462 results in fewer empty lines in configure.
465 * Major changes in Autoconf 2.63 (2008-09-09) [stable]
466 Released by Eric Blake, based on git versions 2.62.*.
468 ** AC_C_BIGENDIAN does not mistakenly report "universal" for some
469 bigendian hosts, a regression introduced with universal binary
472 ** AC_PATH_X now includes /lib64 and /usr/lib64 in its list of default
475 ** AC_USE_SYSTEM_EXTENSIONS no longer conflicts with an external
476 AC_DEFINE([__EXTENSIONS__]). This fixes a regression introduced in
477 2.62 when using macros such as AC_AIX that were made obsolete in
478 favor of the more portable AC_USE_SYSTEM_EXTENSIONS.
480 ** AC_CHECK_TARGET_TOOLS is usable in the non-cross-compile case.
482 ** Newly obsolete macros
483 The following macro has been marked obsolete, since current porting
484 targets can safely assume C89 semantics that signal handlers return
485 void. We have no current plans to remove the macro.
489 ** The macros m4_map and m4_map_sep now ignore any list elements
490 consisting of just empty quotes, and m4_map_sep now expands its
491 separator. This fixes a regression in 2.62 when these macros were
492 first documented, for the sake of clients expecting the semantics
493 that these macros had prior to that time. The new macros m4_mapall
494 and m4_mapall_sep, along with extra quoting of the separator, can
495 be used to get the semantics that m4_map_sep had in 2.62.
497 ** Clients of m4_expand, such as AS_HELP_STRING and AT_SETUP, can now
498 handle properly quoted but otherwise unbalanced parentheses (for
499 some macros, this fixes a regression in 2.62).
501 ** Two new quadrigraphs have been introduced: @{:@ for (, and @:}@ for ),
502 allowing the output of unbalanced parentheses in more contexts.
504 ** The following m4sugar macros are new:
505 m4_cleardivert m4_joinall m4_mapall m4_mapall_sep m4_reverse
506 m4_set_add m4_set_add_all m4_set_contains m4_set_contents
507 m4_set_delete m4_set_difference m4_set_dump m4_set_empty
508 m4_set_foreach m4_set_intersection m4_set_list m4_set_listc
509 m4_set_remove m4_set_size m4_set_union
511 ** The following m4sugar macros now accept multiple arguments, as is the
512 case with underlying m4:
513 m4_defn m4_popdef m4_undefine
515 ** The following m4sugar macros now guarantee linear scaling; they
516 previously had linear scaling with m4 1.6 but quadratic scaling
517 when using m4 1.4.x. All macros built on top of these also gain
518 the scaling improvements.
519 m4_bmatch m4_bpatsubsts m4_case m4_cond m4_do m4_dquote_elt
520 m4_foreach m4_join m4_list_cmp m4_map m4_map_sep m4_max
523 ** AT_KEYWORDS once again performs expansion on its argument, such that
524 AT_KEYWORDS([m4_if([$1], [], [default])]) no longer complains about
525 the possibly unexpanded m4_if [regression introduced in 2.62].
527 ** Config header templates `#undef UNDEFINED /* comment */' do not lead to
528 nested comments any more; regression introduced in 2.62.
531 * Major changes in Autoconf 2.62 (2008-04-05) [stable]
532 Released by Eric Blake, based on git versions 2.61a.*.
534 ** Many optimizations have been applied to make overall execution faster.
536 ** Autotest now makes use of shell functions.
538 ** config.status now uses awk instead of sed also for config headers.
540 - As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
541 values, i.e., backslash-newline combinations are handled correctly.
542 Further, for config headers, the total size of values is not limited by
543 the POSIX length limit of text lines any more, only each single line.
545 ** New config variable `top_build_prefix'.
547 ** New Autoconf macros:
548 AC_AUTOCONF_VERSION AC_OPENMP AC_PATH_PROGS_FEATURE_CHECK
550 ** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.
552 ** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
553 like '__restrict' if the variant spelling is available, as this is
554 more likely to work when mixing C and C++ code.
556 ** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
557 be a string of tokens such that "T y;" is a valid member declaration
560 ** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
561 is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.
563 ** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
564 they did not work for function types. In C++, they now work on any
565 type-id that can be the operand of sizeof; this is similar to C,
566 except it excludes anonymous struct and union types. Formerly,
567 some (but not all) C++ types involving anonymous struct and union
568 were accepted, though this was not documented.
570 ** AC_CONFIG_LINKS now prefers to link against files in the build tree
571 if found, and it works to link against a file of the same name in
572 the source tree, even if both trees coincide.
574 ** AC_INIT no longer alters $@; regression introduced in 2.60.
576 ** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.
578 ** AS_HELP_STRING no longer underquotes its first argument; it also handles
579 the case where the first argument contains single-quoted commas.
580 For example, "AS_HELP_STRING([-a, [--arg[=foo]]], [bar])" produces:
581 " -a, --arg[=foo] bar"
582 Additionally, the macro now takes two additional arguments,
583 indent-column and wrap-column; these should not normally be needed,
584 but can be used to fine-tune how the output text is wrapped.
586 ** AC_PROG_INSTALL now requires an install program that can install multiple
587 files into a target directory.
589 ** The command 'autoconf -' now correctly processes a file from stdin.
591 ** 'autoreconf -m' now honors $MAKE.
593 ** For all of the directory arguments for 'configure', such as '--prefix'
594 or '--bindir', trailing slashes are stripped. As an example, if
595 tab completion in the user's shell appends trailing slashes, the
596 command './configure --prefix=/usr/' will still result in an
597 expanded libdir value of /usr/lib, not /usr//lib.
599 ** `configure --help=recursive' now works in read-only trees and from
600 unconfigured build trees.
602 ** If precious variables differ only in whitespace, then the cache consistency
603 check warns instead of fails, and reuses the old value.
605 ** AT_BANNER is now documented.
607 ** AT_SETUP now handles macro expansions properly when calculating line
610 ** Autotest now determines $srcdir correctly.
612 ** Testsuites built by autotest now accept a -C/--directory=DIR option
613 to adjust the working directory prior to creating files.
615 ** Autoconf now requires GNU M4 1.4.5 or later. Earlier versions of M4 have
616 a bug in macro tracing that interferes with the interaction between
617 Autoconf and Automake. GNU M4 1.4.11 or later is recommended. The
618 configure search for a working M4 is improved.
620 ** For portability with the eventual M4 2.0, macros should no longer use
621 anything larger than $9 to refer to arguments.
623 ** Documentation for m4sugar is improved.
625 - The following macros were previously available as undocumented
626 interfaces; the macros are now documented as stable interfaces.
628 __oline__ m4_assert m4_bmatch m4_bpatsubsts m4_car m4_case
629 m4_cdr m4_default m4_divert_once m4_divert_pop m4_divert_push
630 m4_divert_text m4_do m4_errprintn m4_fatal m4_flatten
631 m4_ifndef m4_ifset m4_ifval m4_ifvaln m4_location
632 m4_n m4_shiftn m4_strip m4_warn
634 - The following macros were previously available as undocumented
635 interfaces, but had bug fixes or semantic changes as part of this
636 release. Packages that relied on the undocumented behavior
637 should be analyzed to make sure they will still work with the
638 new documented behavior.
640 m4_cmp m4_list_cmp m4_join m4_map m4_map_sep m4_sign
641 m4_text_box m4_text_wrap m4_version_compare
643 - The m4_wrap macro used to have unspecified order, but now
644 guarantees FIFO order. m4_wrap_lifo was added to guarantee LIFO
647 - Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
648 should consider using the new AC_AUTOCONF_VERSION instead.
650 - m4sugar macros that are not documented in the manual are still
651 deemed experimental, and should not be used outside of Autoconf.
653 ** The m4sugar macros m4_append and m4_append_uniq, first documented in
654 2.60, have been fixed to treat both the string and the separator
655 arguments consistently with regards to quoting. Prior to this fix,
656 m4_append_uniq could mistakenly duplicate entries if the expansion
657 of the separator resulted in a different string (for example, if it
658 contained quotes, a comma, or a macro name). However, it means
659 that programs previously using
660 m4_append([name], [string], [[, ]])
661 are now using a four-character separator instead of the intended
662 comma and space. If you need portability to earlier versions of
663 Autoconf, you can insert the following snippet after AC_INIT but
664 before any other macro expansions, to enforce the new semantics:
665 m4_pushdef([m4_append], [m4_define([$1],
666 m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
667 Additionally, m4_append_uniq now takes optional parameters that can
668 be used to take action depending on whether anything was appended,
669 and warns if a non-empty separator occurs within the string being
670 appended, since that can lead to duplicates.
672 ** The following m4sugar macros are new:
673 m4_append_uniq_w m4_apply m4_combine m4_cond m4_count
674 m4_dquote_elt m4_echo m4_expand m4_ignore m4_make_list m4_max
675 m4_min m4_newline m4_shift2 m4_shift3 m4_unquote m4_wrap_lifo
677 ** Warnings are now generated by default when an installer invokes
678 'configure' with an unknown --enable-* or --with-* option.
679 These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
680 macro, or by invoking 'configure' with --disable-option-checking.
682 ** Existing obsolete macros
683 The documentation for the following macros is adjusted to make it
684 more clear that they have previously been marked obsolete, as their
685 functionality can be accomplished by other macros. We have no
686 current plans to remove them from Autoconf.
688 AC_ENABLE AC_STRUCT_ST_BLKSIZE AC_STRUCT_ST_RDEV AC_WITH
690 ** Newly obsolete macros
691 The following macros have been marked obsolete, as they only
692 perform a subset of AC_USE_SYSTEM_EXTENSIONS. We have no current
693 plans to remove them.
695 AC_AIX AC_GNU_SOURCE AC_ISC_POSIX AC_MINIX
697 ** AC_C_LONG_DOUBLE is obsolescent.
698 The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
699 tests for problems that are so old that it is no longer of
700 practical importance on current systems. New programs need not use
701 AC_C_LONG_DOUBLE. We have no current plans to remove it.
703 ** AC_DIAGNOSE, AC_WARNING, and AC_FATAL are obsolescent.
704 The documentation now favors the use of M4sugar macros m4_warn and
705 m4_fatal, since the naming makes it more obvious that the
706 diagnostics are associated with M4 expansion (ie. when running
707 `autoconf'), and offers less confusion with the AC_MSG_ERROR,
708 AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
709 when running `configure'. We have no current plans to remove these
713 * Major changes in Autoconf 2.61a (2006-12-11)
715 ** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
716 on many platforms. This has been fixed.
718 ** AC_FUNC_SETVBUF_REVERSED is now obsolete. It is still defined for backward
719 compatibility but it does nothing. The macro was already
720 obsolescent, as the last systems to have the problem were those
721 based on SVR2, which became obsolete in 1987. The macro had bugs
722 on some modern systems and could no longer be maintained reliably
723 due to lack of ancient systems to test it on.
725 ** config.status now uses awk instead of sed for most substitutions, for speed.
727 - As a side effect multi-line values of substituted variables no
728 longer have a small limit in total size, though for portability
729 each line should not exceed the POSIX length limit for text lines.
731 - It is now documented that Makefile.in should not contain
732 overlapping variable occurrences, e.g., @VAR1@VAR2@.
733 Autoconf's behavior was always iffy in such cases, and the
734 awk implementation has changed the behavior.
736 ** Many uses of 'echo' have been rewritten so that Autoconf-generated
737 scripts have fewer problems with strings or file names containing
738 embedded special characters such as backslash or leading "-". This
739 was implemented by using `printf '%s\n' "$foo"' instead of `echo
740 "$foo"' when printf works. Due to the implementation technique
741 used, Autoconf-generated scripts now run considerably more slowly
742 on ancient implementations lacking printf. However, this should
743 not be a problem, since Autoconf-generated scripts in practice
744 invariably find a more-modern shell these days.
747 * Major changes in Autoconf 2.61 (2006-11-17)
749 ** New macros AC_C_FLEXIBLE_ARRAY_MEMBER, AC_C_VARARRAYS.
751 ** AC_ARG_ENABLE and AC_ARG_WITH now allow '.' in feature and package names.
754 * Major changes in Autoconf 2.60b (2006-10-22)
757 Autoconf-generated shell scripts no longer export BIN_SH, due to
758 configuration hassles with this. Installers who need BIN_SH in
759 their environment should set it before invoking 'configure' and
760 'make'. As far as we know, this affects only Unixware installations.
762 ** Obsolescent macros
763 The documentation now says that the following macros are obsolescent,
764 as they are superseded by Gnulib:
766 AC_FUNC_FNMATCH AC_FUNC_FNMATCH_GNU AC_FUNC_GETLOADVG AC_REPLACE_FNMATCH
768 New programs should use the Gnulib counterparts of these macros.
769 We have no current plans to remove them from Autoconf.
771 ** AC_COMPUTE_INT no longer caches or reports results.
773 ** AC_CHECK_DECL now also works with aggregate objects.
775 ** AC_USE_SYSTEM_EXTENSIONS now defines _TANDEM_SOURCE for NonStop platforms.
777 ** GNU M4 1.4.7 or later is now recommended.
780 New M4sugar macro, which is more secure than the POSIX M4 maketemp.
783 Now an alias for m4_mkstemp.
785 * Major changes in Autoconf 2.60a (2006-08-25)
787 ** GNU M4 1.4.6 or later is now recommended.
789 ** The check for C99 now tests for varargs macros, as documented.
790 It also tests that the preprocessor supports 64-bit integers.
792 ** Autoconf now uses constructs like "#ifdef HAVE_STDLIB_H" rather than
793 "#if HAVE_STDLIB_H", so that it now works with "gcc -Wundef -Werror".
795 ** The functionality of the undocumented _AC_COMPUTE_INT is now provided
796 by a public and documented macro, AC_COMPUTE_INT. The parameters to the
797 two macros are different, so autoupdate will not change the old private name
798 to the new one. _AC_COMPUTE_INT may be removed in a future release.
800 ** AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT now require
801 that long long types be at least 64 bits wide, as C99 and tradition
802 requires. Formerly, they accepted implementations of any width.
805 * Major changes in Autoconf 2.60
807 Released 2006-06-23, by Ralf Wildenhues.
809 ** Autoconf no longer depends on whether m4wrap is FIFO (as Posix requires)
810 or LIFO (as in GNU M4 1.4.x). GNU M4 2.0 is expected to conform to Posix
811 here, so m4wrap/m4_wrap users should no longer depend on LIFO behavior.
813 ** Provide a way to turn off warnings about the changed directory variables.
815 * Major changes in Autoconf 2.59d
817 Released 2006-06-05, by Ralf Wildenhues.
819 ** GNU make now recommended for VPATH builds
820 INSTALL now suggests VPATH builds (e.g., "sh ../srcdir/configure")
821 only if you use GNU make. In practice, other 'make' implementations
822 have too many subtle incompatibilities in their support for VPATH.
823 Many packages (including Autoconf itself) are portable to other
824 'make' implementations, but some packages are not, and recommending
825 GNU make keeps the installation instructions simpler.
827 ** Even more safety checks for the new Directory variables:
828 Warn about suspicious `${datarootdir}' found in config files output.
830 ** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
831 These never-documented macros and variables have been marked with
832 comments saying that they may be removed in a future release,
833 because their use can lead to unintended code being executed.
834 If you need functionality that only these macros or variables
835 currently supply, please write bug-autoconf@gnu.org.
837 ** AC_SUBST, AC_DEFINE
838 Literal arguments to these are passed to m4_pattern_allow now.
841 Passing 'ac_cv_prog_cc_stdc=no' to 'configure' now sets ac_cv_prog_cc_c99
842 and ac_cv_prog_cc_c89 to 'no' as well, for backward compatibility with
843 obsolete K&R tests in the Automake test suite.
852 Now more robust with special characters in file names, or when
853 multiple processes create the same directory at the same time.
855 ** Obsolescent macros
856 The documentation now says that the following macros are obsolescent:
857 they test for problems that are so old that they are no longer of
858 practical importance on current systems.
860 AC_C_BACKSLASH_A AC_FUNC_MEMCMP AC_HEADER_DIRENT
861 AC_C_CONST AC_FUNC_SELECT_ARGTYPES AC_HEADER_STAT
862 AC_C_PROTOTYPES AC_FUNC_SETPGRP AC_HEADER_STDC
863 AC_C_STRINGIZE AC_FUNC_SETVBUF_REVERSED AC_HEADER_SYS_WAIT
864 AC_C_VOLATILE AC_FUNC_STAT AC_HEADER_TIME
865 AC_FUNC_CLOSEDIR_VOID AC_FUNC_STRFTIME AC_ISC_POSIX
866 AC_FUNC_GETPGRP AC_FUNC_UTIME_NULL AC_PROG_GCC_TRADITIONAL
867 AC_FUNC_LSTAT AC_FUNC_VPRINTF AC_STRUCT_TM
869 New programs need not use these macros. We have no current plans to
873 For compatibility with future Libtool 2.0, autoreconf will invoke
874 libtoolize with the option `--ltdl' now, if LT_CONFIG_LTDL_DIR is
877 * Major changes in Autoconf 2.59c
879 Released 2006-04-12, by Ralf Wildenhues.
881 ** The configure command now redirects standard input from /dev/null,
882 to help avoid problems with subsidiary commands that might mistakenly
883 read standard input. AS_ORIGINAL_STDIN_FD points to the original
884 standard input before this redirection, if you really want configure to
885 read from standard input.
887 ** Directory variables adjusted to recent changes in the GNU Coding Standards.
888 The following directory variables are new:
890 datarootdir read-only architecture-independent data root [PREFIX/share]
891 localedir locale-specific message catalogs [DATAROOTDIR/locale]
892 docdir documentation root [DATAROOTDIR/doc/PACKAGE]
893 htmldir html documentation [DOCDIR]
894 dvidir dvi documentation [DOCDIR]
895 pdfdir pdf documentation [DOCDIR]
896 psdir ps documentation [DOCDIR]
898 The following variables have new default values:
900 datadir read-only architecture-independent data [DATAROOTDIR]
901 infodir info documentation [DATAROOTDIR/info]
902 mandir man documentation [DATAROOTDIR/man]
904 This means that if you use any of `@datadir@', `@infodir@', or
905 `@mandir@' in a file, you will have to ensure `${datarootdir}' is
906 defined in this file. As a temporary measure, if any of those are
907 found but no mention of `datarootdir', the substitutions will be
908 replaced with values that do not contain `${datarootdir}', and a
909 warning will be issued.
911 ** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
912 a trailing slash. Similar change will be made to ac_top_builddir in a
913 future release; the old style value, which matches (../)*, is (and will
914 continue to be) available as ac_top_build_prefix.
917 New macro to check for support of 'typeof' syntax a la GNU C.
919 ** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
920 New "once-only" variants of commonly-used macros, to make 'configure'
921 smaller and faster in common cases.
924 New macro to check for strtold with C99 semantics.
927 New macro that lets builder disable assertions at 'configure'-time.
930 Now checks for X11/Xlib.h and XrmInitialize (X proper) rather than
931 X11/Intrinsic.h and XtMalloc (Xt).
933 ** AC_PRESERVE_HELP_ORDER
934 New macro that causes `configure' to display help strings for AC_ARG_ENABLE
935 and AC_ARG_WITH arguments in one region, in the order defined. The default
936 behavior is to group options of each classes separately.
938 ** AC_PROG_CC, AC_PROG_CXX
939 No longer automatically arrange to declare the 'exit' function of C,
940 when a C++ compiler is used. Standard Autoconf macros no longer use
941 'exit', so this is no longer an issue for them. If you use C++, and
942 want to call 'exit', you'll have to arrange for its declaration
943 yourself. But we now suggest you return from 'main' instead.
945 ** AC_PROG_CC_C89, AC_PROG_CC_C99
946 New macros for ISO C99 support. AC_PROG_CC_C89 and AC_PROG_CC_C99
947 check for ANSI C89 and ISO C99 support respectively.
950 Has been unobsoleted, and will check if the compiler supports ISO
951 C99, falling back to ANSI C89 if not. ac_cv_prog_cc_stdc is
952 retained for backwards compatibility, assuming the value of
953 ac_cv_prog_cc_c99 or ac_cv_prog_cc_c89 (whichever is valid, in
956 ** AC_STRUCT_DIRENT_D_INO, AC_STRUCT_DIRENT_D_TYPE
957 New macros for checking commonly-used members of struct dirent.
960 The substituted value can now contain newlines.
963 The substitution now occurs only when @variable@ is on a line by itself,
964 optionally surrounded by spaces and tabs. The whole line is replaced.
966 ** AC_TYPE_LONG_DOUBLE, AC_TYPE_LONG_DOUBLE_WIDER
967 New macros to check for long double, and whether it is wider than double.
968 The old macro AC_C_TYPE_LONG_DOUBLE has been marked as obsolete;
969 applications should switch to the new macro.
971 ** AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, AC_TYPE_INT64_T,
972 AC_TYPE_INTMAX_T, AC_TYPE_INTPTR_T, AC_TYPE_LONG_LONG_INT, AC_TYPE_SSIZE_T,
973 AC_TYPE_UINT8_T, AC_TYPE_UINT16_T, AC_TYPE_UINT32_T, AC_TYPE_UINT64_T,
974 AC_TYPE_UINTMAX_T, AC_TYPE_UINTPTR_T, AC_TYPE_UNSIGNED_LONG_LONG_INT
975 New macros to check for C99 and POSIX types.
977 ** AC_USE_SYSTEM_EXTENSIONS
978 New macro to enable extensions to Posix.
981 New macro which is defined to the name of the first declared config header
982 or undefined if no config headers have been declared yet.
985 The macro correctly handles quadrigraphs now.
987 ** AS_BOURNE_COMPATIBLE, AS_SHELL_SANITIZE, AS_CASE
988 These macros are new or published now.
991 New macro for copyright notices in testsuite files.
993 ** ALLOCA, LIBOBJS, LTLIBOBJS
994 Object names added to these variables are now prefixed with `${LIBOBJDIR}',
995 as in `${LIBOBJDIR}alloca.o'. LIBOBJDIR is meant to be defined from
996 `Makefile.in' in case the object files lie in a different directory.
997 The LIBOBJDIR feature is experimental.
1000 Supports --no-recursive now.
1002 ** New macros to support Erlang/OTP.
1003 New macros for configuring paths to Erlang tools and libraries:
1004 AC_ERLANG_PATH_ERLC, AC_ERLANG_NEED_ERLC, AC_ERLANG_PATH_ERL,
1005 AC_ERLANG_NEED_ERL, AC_ERLANG_CHECK_LIB, AC_ERLANG_SUBST_ROOT_DIR,
1006 AC_ERLANG_SUBST_LIB_DIR.
1008 New macros for configuring installation of Erlang libraries:
1009 AC_ERLANG_SUBST_INSTALL_LIB_DIR, AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR.
1011 ** The manual now mentions Gnulib more prominently.
1013 ** New macros to support Objective C.
1014 AC_PROG_OBJC, AC_PROG_OBJCPP.
1016 * Major changes in Autoconf 2.59b
1018 Released 2004-08-20, by Paul Eggert.
1021 New macro that computes the default alignment of a type.
1023 ** AC_CHECK_TOOL, AC_PATH_TOOL, AC_CHECK_TOOLS
1024 When cross-compiling, these macros will give a warning if the tool
1025 is not prefixed. In the future, unprefixed cross tools will not
1026 be detected; please consult the info documentation for information
1027 about the reason of this change.
1029 ** AC_CHECK_TARGET_TOOL, AC_PATH_TARGET_TOOL, AC_CHECK_TARGET_TOOLS
1030 New macros that detect programs whose name is prefixed with the
1031 target type, if the build type and target type are different.
1033 ** AC_REQUIRE_AUX_FILE
1034 New trace macro that declares expected auxiliary files.
1037 New macro that tests for a grep program that accepts as a long a line
1040 ** AC_PROG_EGREP, AC_PROG_FGREP
1041 These macros now require AC_PROG_GREP, and try EGREP="$GREP -E" and
1042 FGREP="$GREP -F" respectively if possible, or else run a path search for
1043 a program that accepts as long a line as possible.
1046 New macro that tests for a sed program that truncates as few characters
1049 * Major changes in Autoconf 2.59
1051 Released 2003-11-04, by Akim Demaille
1053 ** ac_abs_builddir etc.
1054 Absolute file names were actually relative in 2.58.
1056 * Major changes in Autoconf 2.58
1058 Released 2003-11-04, by Akim Demaille
1061 core.* files are no longer removed, as they may be valid user files.
1063 ** autoreconf and auxiliary directory
1064 Autoreconf creates the auxiliary directory if needed. This is
1065 especially useful for initial "bootstrapping" of fresh CVS checkouts.
1067 ** AC_CONFIG_MACRO_DIR
1068 Use this macro to declare the directory for local M4 macros for aclocal.
1071 No longer includes twice the same file in LIBOBJS if invoked
1074 ** AC_CONFIG_COMMANDS
1075 The directory for its first argument is automatically created. For
1078 AC_CONFIG_COMMANDS([src/modules.hh], [...])
1080 $top_builddir/src/ is created if needed.
1082 ** Autotest and local.at
1083 The optional file local.at is always included in Autotest test suites.
1086 The warnings are always issued, including with cached runs.
1087 This became a significant problem since aclocal and automake can
1088 run autoconf behind the scene.
1090 ** autoheader warnings
1091 The warnings of autoheader can be turned off, using --warning.
1092 For instance, -Wno-obsolete disables the complaints about acconfig.h
1093 and other deprecated constructs.
1096 AC_C_RESTRICT, AC_INCLUDES_DEFAULT, AC_LANG_ASSERT, AC_LANG_WERROR,
1099 ** AC_DECL_SYS_SIGLIST
1103 Now checks that mktime is the inverse of localtime.
1105 ** Improve DJGPP portability
1106 The Autoconf tools and configure behave better under DJGPP.
1108 ** Present But Cannot Be Compiled
1109 New FAQ section dedicated to the mystic
1111 configure: WARNING: pi.h: present but cannot be compiled
1112 configure: WARNING: pi.h: check for missing prerequisite headers?
1113 configure: WARNING: pi.h: proceeding with the preprocessor's result
1116 ** Concurrent executions of autom4te
1117 autom4te now locks its internal files, which enables concurrent
1118 executions of autom4te, likely to happen if automake, autoconf,
1119 autoheader etc. are run simultaneously.
1122 Use of Libtool 1.5 and higher is encouraged. Compatibility with
1123 Libtool pre-1.4 is not checked.
1126 Testsuites no longer rerun failed tests in verbose mode; instead,
1127 failures are logged while the test is run.
1129 In addition, expected failures can be marked as such.
1131 * Major changes in Autoconf 2.57
1133 Released 2002-12-03 by Paul Eggert.
1135 Bug fixes for problems with AIX linker, with freestanding C compilers,
1136 with GNU M4 limitations, and with obsolete copies of GNU documents.
1138 The Free Documentation License has been upgraded from 1.1 to 1.2.
1140 * Major changes in Autoconf 2.56
1142 Released 2002-11-15 by Akim Demaille.
1144 One packaging problem fixed (config/install-sh was not executable).
1146 * Major changes in Autoconf 2.55
1148 Released 2002-11-14 by Akim Demaille.
1152 Have your configure.ac checked by autoscan ("autoscan").
1153 Try the warning options ("autoreconf -fv -Wall").
1157 - AC_CHECK_HEADER, AC_CHECK_HEADERS
1158 More information on proper use.
1160 - Writing Test Programs
1162 This sections explains how to write good test sources to use with
1163 AC_COMPILE_IFELSE etc. It documents AC_LANG_PROGRAM and so forth.
1165 - AC_FOO_IFELSE vs. AC_TRY_FOO
1167 Explains why Autoconf moves from AC_TRY_COMPILE etc. to
1168 AC_COMPILE_IFELSE and AC_LANG_PROGRAM etc.
1172 - Is more robust to different Gettext installations.
1174 - Produces messages (when --verbose) to be understood by Emacs'
1177 - Supports -W/--warnings.
1180 Once the GNU Build System reinstalled, run `./config.status
1181 --recheck && ./config.status && make' if possible.
1185 - Supports --cache, and --no-cache.
1187 - ~/.autom4te.cfg makes it possible to disable the caching mechanism
1188 (autom4te.cache). See `Customizing autom4te' in the documentation.
1195 Support for the obsoleted options -m, --macrodir, -l, --localdir is
1196 dropped in favor of the safer --include/--prepend-include scheme.
1201 AC_COMPILER_IFELSE, AC_FUNC_MBRTOWC, AC_HEADER_STDBOOL,
1202 AC_LANG_CONFTEST, AC_LANG_SOURCE, AC_LANG_PROGRAM, AC_LANG_CALL,
1203 AC_LANG_FUNC_TRY_LINK, AC_MSG_FAILURE, AC_PREPROC_IFELSE.
1206 Obsoleted macros are kept for Autoconf backward compatibility, but
1207 should be avoided in configure.ac. Running autoupdate is advised.
1208 AC_DECL_SYS_SIGLIST.
1210 - AC_DEFINE/AC_DEFINE_UNQUOTED
1212 We have to stop using the old compatibility scheme --that tried to
1213 avoid useless backslashes-- because Libtool 1.4.3 contains a
1215 AC_DEFINE([error_t], [int],
1216 [Define to a type to use for \`error_t' if it is not
1217 otherwise available.])
1219 We have to quote the single quotes and backslashes with \. The old
1220 compatibility scheme saw that ` was backslashed, and therefore did
1221 not quote the single quote... Failure. Hence, Autoconf 2.54 is not
1222 compatible with Libtool. Autoconf 2.55 is, but in some cases might
1223 produce more \ than wanted.
1225 Please, note that in the future the same problem will happen with
1226 AC_MSG_*: use `autoreconf -f -Wall'.
1230 - Portability of the Autoconf package to Solaris.
1232 - Spurious warnings caused by config.status.
1233 This bug is benign, but painful: on some systems (typically
1234 FreeBSD), warnings such as:
1236 config.status: creating Makefile
1237 mv: Makefile: set owner/group (was: 1357/0): Operation not permitted
1239 could be issued. This is fixed.
1242 Simultaneous executions of config.status are possible again.
1244 - Precious variables accumulation
1246 config.status could stack several copies of the precious variables
1250 ** Plans for later versions
1252 - ./configure <host>
1254 The compatibility hooks with the old scheme will be completely
1255 removed. Please, advice/use `--build', `--host', and `--target'
1258 - AC_CHECK_HEADER, AC_CHECK_HEADERS
1260 The tests will be stricter, please make sure your invocations are
1265 Shell functions will gradually be introduced, probably starting with
1266 Autotest. If you know machines which are in use that you suspect
1267 *not* to support shell functions, please run the test suite of
1268 Autoconf 2.55 on it, and report the results to
1269 bug-autoconf@gnu.org.
1273 Special characters in AC_MSG_* need not be quoted. Currently,
1274 Autoconf has heuristics to decide when a string is escaped, or has
1275 to be escaped. This scheme is fragile, and will be removed; the
1276 only risk is uglified messages. Please, run `autoreconf -f -Wall'
1277 to find occurrences that will be affected.
1279 * Major changes in Autoconf 2.54
1281 Released 2002-09-13 by Akim Demaille.
1285 - autoreconf no longer changes the version of the gettext/po/intl
1286 support files. It now adds the files the correspond to the
1287 AM_GNU_GETTEXT_VERSION declared in configure.ac.
1289 Warning: It now relies on the 'autopoint' program, which is part
1290 of GNU gettext 0.11.4 and newer.
1292 Please note that you need to have a GNU gettext version that
1293 corresponds at least to the AM_GNU_GETTEXT_VERSION declared
1294 in configure.ac. You can upgrade to newer GNU gettext versions,
1295 though, without needing to change configure.ac.
1297 - The -I DIR or --include=DIR option now appends DIR to the include path
1298 instead of prepending; this is for consistency with other GNU tools.
1299 The new -B DIR or --prepend-include=DIR option has the old behavior.
1304 Now handles all the gory details about LIBOBJS and LTLIBOBJS.
1305 Please, remove lines such as
1307 # This is necessary so that .o files in LIBOBJS are also
1308 # built via the ANSI2KNR-filtering rules.
1309 LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
1311 and read the `AC_LIBOBJ vs LIBOBJS' section. Do not define U in
1312 your Makefiles either.
1314 - AC_CONFIG_LINKS now makes copies if it can't make links.
1316 - AC_FUNC_FNMATCH now tests only for POSIX compatibility, reverting to
1317 Autoconf 2.13 behavior. The new macro AC_FUNC_FNMATCH_GNU also
1318 tests for GNU extensions to fnmatch, and replaces fnmatch if needed.
1320 - AC_FUNC_SETVBUF_REVERSED no longer fails when cross-compiling.
1322 - AC_PROG_CC_STDC is integrated into AC_PROG_CC.
1324 - AC_PROG_F77 default search no longer includes cf77 and cfg77.
1328 AC_C_BACKSLASH_A, AC_CONFIG_LIBOBJ_DIR, AC_GNU_SOURCE,
1329 AC_PROG_EGREP, AC_PROG_FGREP, AC_REPLACE_FNMATCH,
1330 AC_FUNC_FNMATCH_GNU, AC_FUNC_REALLOC, AC_TYPE_MBSTATE_T.
1332 - AC_FUNC_GETLOADAVG
1333 looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
1336 Now defines HAVE_MALLOC to 0 if `malloc' does not work, and asks
1337 for an AC_LIBOBJ replacement.
1341 - Spurious complaints from `m4_bmatch' about invalid regular
1342 expressions are suppressed.
1344 - Empty top_builddirs are properly handled.
1346 - AC_CHECK_MEMBER works correctly when the member is an aggregate.
1349 Now colon in the optional path arguments are properly handled.
1351 ** Improved portability
1353 - Both Autoconf the package, and the scripts it produces, should run
1354 more reliably with Zsh. Bear in mind it is the default Bourne shell
1357 - Autoconf and the scripts it produces no longer assume the existence of
1358 the obsolescent commands egrep and fgrep.
1362 - Limitations of Make
1366 The GNATS base moved to
1367 http://bugs.gnu.org/cgi-bin/gnatsweb.pl?database=autoconf
1368 (It is no longer available, though.)
1373 Now contains the list of output variables and files (AC_SUBST,
1376 * Major changes in Autoconf 2.53
1378 Released 2002-03-08 by Akim Demaille.
1382 Perl 5.005_03 or later is required: autom4te is written in Perl and is
1383 needed by autoconf. autoheader, autoreconf, ifnames, and autoscan are
1389 Argument requirements, output variables, defined macros.
1390 - M4sugar, M4sh, Autotest
1392 - Double quoting macros
1393 AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
1395 The Autoconf manual is now distributed under the terms of the GNU FDL.
1396 - Section `Hosts and Cross-Compilation'
1397 Explains the rationale for the 2.5x changes in the cross-compilation
1398 chain, and in the relationships between build, host, and target
1400 Emphasizes that `cross-compilation' == `--host is given'.
1401 If you are working on compilers etc., be sure to read this section.
1402 - Section `AC_LIBOBJ vs. LIBOBJS'
1403 Explains why assigning LIBOBJS directly is now an error.
1404 Details how to update the code.
1409 Now used instead of hard coded line numbers.
1410 This eases the comparison of `configure's, and diminishes the
1411 pressure over control version archives.
1412 Automatic replacement for shells that don't support this feature.
1413 - New output variables
1414 @builddir@, @top_builddir@, @abs_srcdir@, @abs_top_srcdir@, @abs_builddir@,
1419 Autoconf and Autotest modes are provided.
1424 New, used by the Autoconf suite to cache and speed up most processing.
1426 Supported by autom4te, autoconf and autoheader.
1428 Replaces --autoconf-dir and --localdir in autoconf, autoheader,
1429 autoupdate, and autoreconf.
1431 No longer passes --cygnus, --foreign, --gnits, --gnu, --include-deps:
1432 automake options are to be given via AUTOMAKE_OPTIONS.
1434 Runs gettextize and libtoolize when appropriate.
1436 --m4dir is no longer supported.
1438 Now runs only in the specified directories, defaulting to `.',
1439 but understands AC_CONFIG_SUBDIRS for dependent directories.
1440 Before, it used to run on all the `configure.ac' found in the
1442 Independent packages are properly updated.
1446 - The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
1448 Under the user pressure, $? is finally available. Probably a mistake.
1449 - AC_F77_LIBRARY_LDFLAGS now supports the HP/UX f90 compiler.
1450 - Precious variables accumulation
1451 config.status could stack several copies of the precious variables
1453 - AC_PATH_PROG and family.
1454 Works properly when given a literal path.
1456 Somewhere since 2.13, the result had been reversed.
1460 - AC_C_BIGENDIAN supports the cross-compiling case.
1461 - AC_C_BIGENDIAN accepts ACTION-IF-TRUE, ACTION-IF-FALSE, and
1462 ACTION-IF-UNKNOWN arguments. All are optional, and the default
1463 for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
1465 - AC_C_LONG_DOUBLE now succeeds only if `long double' has more range or
1466 precision than `double'.
1471 It now defines the preprocessor symbols PACKAGE_NAME,
1472 PACKAGE_TARNAME, PACKAGE_VERSION, PACKAGE_STRING, and
1476 Admits a fourth optional parameter: the tar name.
1478 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS.
1479 Provide the user with srcdir, ac_srcdir, ac_top_srcdir, ac_builddir,
1480 ac_top_builddir, ac_abs_srcdir, ac_abs_top_srcdir, ac_abs_builddir,
1481 ac_abs_top_builddir.
1483 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS and AC_OUTPUT.
1484 Are much less expensive when using long lists of files.
1487 Works with shell variables, and non alphanumeric names.
1491 - AC_FUNC_STRERROR_R now sets STRERROR_R_CHAR_P, not HAVE_WORKING_STRERROR_R,
1492 because POSIX 1003.1-200x draft 7 says strerror_r returns int, not char *.
1494 - AC_FUNC_STRTOD substitutes POW_LIB.
1499 * Major changes in Autoconf 2.52
1501 Released 2001-07-18 by Akim Demaille.
1506 This feature was present in autoconf 2.50 but was not documented.
1507 For example, `@<:@' is translated to `[' just before output. This
1508 is useful when writing strings that contain unbalanced quotes, or
1509 other hard-to-quote constructs.
1510 - m4_pattern_forbid, m4_pattern_allow
1511 - Tips for upgrading from 2.13.
1512 - Using autoscan to maintain a configure.ac.
1515 - Now include stdint.h.
1516 - sys/types.h and sys/stat.h are guarded.
1517 - strings.h is included if available, and not conflicting with string.h.
1520 - The test suite is more robust and presents less false failures.
1521 - Invocation of GNU M4 now robust to POSIXLY_CORRECT.
1522 - configure accepts --prefix='' again.
1523 - AC_CHECK_LIB works properly when its first argument is not a
1525 - HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
1526 - build_, host_, and target_alias are AC_SUBST as in 2.13.
1527 - AC_ARG_VAR properly propagates precious variables inherited from the
1528 environment to ./config.status.
1529 - Using --program-suffix/--program-prefix is portable.
1530 - Failures to detect the default compiler's output extension are less
1532 - `config.status foo' works properly when `foo' depends on variables
1533 set in an AC_CONFIG_THING INIT-CMD.
1534 - autoheader is more robust to broken input.
1535 - Fixed Fortran name-mangling and link tests on a number of systems,
1536 e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
1539 - AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
1540 specify pre-includes. In this case, the headers are compiled with
1541 cc, not merely preprocessed by cpp. Therefore it is the _usability_
1542 of a header which is checked for, not just its availability.
1543 - AC_ARG_VAR refuses to run configure when precious variables have
1545 - Versions of compilers are dumped in the logs.
1546 - AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
1549 - AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
1550 - AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
1551 - AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
1552 AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
1553 Be sure to read `Upgrading from Version 2.13' to understand why
1554 running `autoupdate' is needed.
1555 - AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
1556 a main-like routine is required/possible when linking C/C++ with
1557 Fortran. Users of e.g. AC_F77_WRAPPERS should be aware of these.
1558 - AC_FUNC_GETPGRG behaves better when cross-compiling.
1560 * Major changes in Autoconf 2.51
1561 There was no release of Autoconf 2.51 since some packagers had used
1562 this version number without permission to ship intermediary versions
1563 of 2.50. The version was skipped to avoid confusion.
1565 * Major changes in Autoconf 2.50
1567 Released 2001-05-21 by Akim Demaille.
1569 ** Lots of bug fixes
1570 There have been far too many to enumerate them here. Check out
1571 ChangeLog if you really want to know more.
1573 ** Improved documentation
1574 In particular, portability issues are better covered.
1577 All the standard GNU Makefile targets are supported. The layout has
1578 changed: m4/ holds the M4 extensions Autoconf needs for its
1579 configuration, doc/ contains the documentation, and tests/ contains
1582 ** Man pages are provided
1583 For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
1584 config.guess, config.sub.
1588 Provides a safe and powerful means to trace the macro uses. This
1589 provide the parsing layer for tools which need to `study'
1593 Specify what category of warnings should be enabled.
1595 - When recursing into subdirectories, try for configure.gnu before
1596 configure to adapt for packages not using autoconf on case-insensitive
1600 More errors are now caught (circular AC_REQUIRE dependencies,
1601 AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
1602 etc.). In addition, their location and call stack are given.
1605 autoupdate is much more powerful, and is able to provide the glue code
1606 which might be needed to move from an old macro to its newer
1609 You are strongly encouraged to use it to modernize both your
1610 `configure.in' and your .m4 extension files.
1613 The internal machinery of autoheader has completely changed. As a
1614 result, using `acconfig.h' should be considered to be obsoleted, and
1615 you are encouraged to get rid of it using the AH macros.
1620 ** Fortran 77 compilers
1621 Globally, the support for Fortran 77 is considerably improved.
1623 Support for automatically determining a Fortran 77 compiler's
1624 name-mangling scheme. New CPP macros F77_FUNC and F77_FUNC_ are
1625 provided to wrap C/C++ identifiers, thus making it easier and more
1626 transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
1627 call C/C++ routines. See the Texinfo documentation for details.
1630 The test suite no longer uses DejaGNU. It should be easy to submit
1631 test cases in this new framework.
1634 - --help, --help=long, -hl
1635 no longer dumps useless items.
1637 lists only specific options.
1638 - --help=recursive, -hr
1639 displays the help of all the embedded packages.
1640 - Remembers environment variables when reconfiguring.
1641 The previous scheme to set envvar before running configure was
1643 what prevented configure from remembering the environment in which
1644 it was run, therefore --recheck was run in an inconsistent
1645 environment. Now, one should run
1647 and then --recheck will work properly. Variables declared with
1648 AC_ARG_VAR are also preserved.
1650 $build defaults to `config.guess`, $host to $build, and then $target
1652 Cross-compilation is a global status of the package, it no longer
1653 depends upon the current language.
1654 Cross compilation is enabled iff the user specified `--host'.
1655 `configure' now fails if it can't run the executables it compiles,
1656 unless cross-compilation is enabled.
1658 The cache file is disabled by default. The new options
1659 `--config-cache', `-C' set the cache to `config.cache'.
1663 Much faster on most architectures.
1664 - concurrent executions
1665 It is safe to use `make -j' with config.status.
1666 - human interface improved
1667 It is possible to invoke
1668 ./config.status foobar
1669 instead of the former form (still valid)
1670 CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
1671 CONFIG_FILES=foobar:foo.in:bar.in \
1673 The same holds for configuration headers and links.
1674 You can instantiate unknown files and headers:
1675 ./config.status --header foo.h:foo.h.in --file bar:baz
1676 - has a useful --help
1677 - accepts special file name "-" for stdin/stdout
1682 Specify additional copyright information.
1685 Now expects the identity of the package as argument.
1689 Most macros, if not all, now strictly follow the `one quotation
1690 level' rule. This results in a more predictable expansion.
1693 A sly bug in the AC_REQUIRE machinery, which could produce incorrect
1694 configure scripts, was fixed by Axel Thimm.
1698 Document and ask for the registration of an envvar.
1701 Specifies the file which `configure' should look for when trying to
1702 find the source tree (used to be handled by AC_INIT).
1704 - AC_CONFIG_COMMANDS
1705 To add new actions to config.status. Should be used instead of
1709 Replaces AC_LINK_FILES.
1711 - AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
1712 AC_CONFIG_LINKS, and AC_CONFIG_FILES
1713 They now obey sh: you should no longer use shell variables as
1714 argument. Instead of
1716 test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
1717 AC_CONFIG_SUBDIRS($my_subdirs)
1721 if test "$package_foo_enabled" = yes; then
1722 AC_CONFIG_SUBDIRS(foo)
1726 To format an Autoconf macro's help string so that it looks pretty
1727 when the user executes `configure --help'.
1730 ** Generic Test Macros
1732 The interface of the AC_CHECK families of macros (decl, header,
1733 type, member, func) is now uniform. They support the same set of
1736 - AC_CHECK_DECL, AC_CHECK_DECLS
1737 To check whether a symbol is declared.
1739 - AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
1740 No longer need a cross-compilation default.
1743 The test it performs is much more robust than previously, and makes
1744 it possible to test builtin types in addition to typedefs.
1745 It is now schizophrenic:
1746 - AC_CHECK_TYPE(TYPE, REPLACEMENT)
1747 remains for backward compatibility, but its use is discouraged.
1748 - AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
1749 behaves exactly like the other AC_CHECK macros.
1752 Checks whether given types are supported by the system.
1754 - AC_CHECK_MEMBER, AC_CHECK_MEMBERS
1755 Check for given members in aggregates (e.g., pw_gecos in struct
1759 Checks if the compiler supports ISO C, included when needs special
1763 Checking whether the preprocessor indicates missing includes by the
1764 error code. stderr is checked by AC_TRY_CPP only as a fallback.
1767 Takes a language as argument and replaces AC_LANG_C,
1768 AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
1770 - AC_LANG_PUSH, AC_LANG_POP
1771 Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
1774 - AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
1775 AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
1776 AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
1780 Sets GETGROUPS_LIBS.
1782 - AC_FUNC_GETLOADAVG
1783 Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
1786 Now integrates `AC_DECL_YYTEXT' which is obsoleted.
1789 Arrange for large-file support.
1791 - AC_EXEEXT, AC_OBJEXT
1792 You are no longer expected to use them: their computation is
1793 performed by default.
1795 ** C++ compatibility
1796 Every macro has been revisited in order to support at best CC=c++.
1798 Major changes in Autoconf 2.14:
1799 There was no release of GNU Autoconf 2.14.
1801 Major changes in Autoconf 2.13:
1803 Released 1999-05-01 by Ben Elliston.
1805 * Support for building on 32-bit Windows systems where the only available C or
1806 C++ compiler is the Microsoft Visual C++ command line compiler
1807 (`cl'). Additional support for building on 32-bit Windows systems which are
1808 using the Cygwin or Mingw32 environments.
1809 * Support for alternative object file and executable file extensions.
1810 On 32-bit Windows, for example, these are .obj and .exe. These are discovered
1811 using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
1812 @EXEEXT@ in the output, respectively.
1813 * New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
1814 AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
1815 AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
1816 * AC_DEFINE now has an optional third argument for a description to be
1817 placed in the config header input file (e.g. config.h.in).
1818 * The C++ code fragment compiled for the C++ compiler test had to be
1819 improved to include an explicit return type for main(). This was
1820 causing failures on systems using recent versions of the EGCS C++
1822 * Fixed an important bug in AC_CHECK_TYPE that would cause a configure
1823 script to report that `sometype_t' was present when only `type_t'
1825 * Merge of the FSF version of config.guess and config.sub to modernize
1826 these scripts. Add support for a few new hosts in config.guess.
1827 Incorporate latest versions of install-sh, mkinstalldirs and
1828 texinfo.tex from the FSF.
1829 * autoreconf is capable of running automake if necessary (and
1831 * Support for Fortran 77. See the Texinfo documentation for details.
1832 * Bug fixes and workarounds for quirky bugs in vendor utilities.
1834 Major changes in Autoconf 2.12:
1836 Released 1996-11-26 by David J. MacKenzie
1838 * AC_OUTPUT and AC_CONFIG_HEADER can create output files by
1839 concatenating multiple input files separated by colons, like so:
1840 AC_CONFIG_HEADER(config.h:conf.pre:config.h.in:conf.post)
1841 AC_OUTPUT(Makefile:Makefile.in:Makefile.rules)
1842 The arguments may be shell variables, to compute the lists on the fly.
1843 * AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
1844 * New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
1847 Major changes in Autoconf 2.11:
1849 Released November 18th, 1996, by David J. MacKenzie
1851 * AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
1852 They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
1853 * AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
1854 * AC_CONFIG_HEADER expands shell variables in its argument.
1855 * New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
1856 * The "checking..." messages and the source code for test programs that
1857 fail are saved in config.log.
1858 * Another workaround has been added for seds with small command length limits.
1859 * config.sub and config.guess recognize more system types.
1862 Major changes in Autoconf 2.10:
1864 Released May 7th, 1996, by Roland McGrath
1867 * The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
1868 changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
1870 Major changes in Autoconf 2.9:
1872 Released March 16th, 1996, by Roland McGrath
1876 Major changes in Autoconf 2.8:
1878 Released March 8th, 1996, by Roland McGrath
1882 Major changes in Autoconf 2.7:
1884 Released November 22nd, 1995, by David J. MacKenzie
1888 Major changes in Autoconf 2.6:
1890 Released November 20th, 1995, by David J. MacKenzie
1894 Major changes in Autoconf 2.5:
1896 Released November 17th, 1995, by Roland McGrath
1898 * New configure options --bindir, --libdir, --datadir, etc., with
1899 corresponding output variables.
1900 * New macro: AC_CACHE_CHECK, to make using the cache easier.
1901 * config.log contains the command being run as well as any output from it.
1902 * AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
1903 * AC_PROG_INSTALL doesn't cache a name for install-sh, for sharing caches.
1904 * AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
1905 AC_CHECK_TOOL can search a path other than $PATH.
1906 * AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
1908 Major changes in Autoconf 2.4:
1910 Released June 14th, 1995, by David J. MacKenzie
1912 * Fix a few bugs found by Emacs testers.
1914 Major changes in Autoconf 2.3:
1916 Released March 27th, 1995, by David J. MacKenzie
1918 * Fix the cleanup trap in several ways.
1919 * Handle C compilers that are picky about option placement.
1920 * ifnames gets the version number from the right directory.
1922 Major changes in Autoconf 2.2:
1924 Released March 8th, 1995, by David J. MacKenzie
1926 * The ifnames utility is much faster but requires a "new awk" interpreter.
1927 * AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
1928 library before existing libs, not after, in case it uses them.
1929 * New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
1930 * Lots of bug fixes.
1931 * Many additions to the TODO file :-)
1933 Major changes in Autoconf 2.1:
1935 Released November 4th, 1994, by David J. MacKenzie
1938 * More explanations in the manual.
1939 * Fix a spurious failure in the testsuite.
1940 * Clarify some warning messages.
1941 * autoreconf by default only rebuilds configure and config.h.in files
1942 that are older than any of their particular input files; there is a
1943 --force option to use after installing a new version of Autoconf.
1945 Thanks to everybody who's submitted changes and additions to Autoconf!
1946 I've incorporated many of them, and am still considering others for
1947 future releases -- but I didn't want to postpone this release indefinitely.
1949 Caution: don't indiscriminately rebuild configure scripts with
1950 Autoconf version 2. Some configure.in files need minor adjustments to
1951 work with it; the documentation has a chapter on upgrading. A few
1952 configure.in files, including those for GNU Emacs and the GNU C
1953 Library, need major changes because they relied on undocumented
1954 internals of version 1. Future releases of those packages will have
1955 updated configure.in files.
1957 It's best to use GNU M4 1.3 (or later) with Autoconf version 2.
1958 Autoconf now makes heavy use of M4 diversions, which were implemented
1959 inefficiently in GNU M4 releases before 1.3.
1961 Major changes in Autoconf 2.0:
1963 Released October 26th, 1994, by David J. MacKenzie
1965 ** New copyright terms:
1966 * There are no restrictions on distribution or use of configure scripts.
1969 * Autoconf manual is reorganized to make information easier to find
1970 and has several new indexes.
1971 * INSTALL is reorganized and clearer and is now made from Texinfo source.
1974 * autoscan to generate a preliminary configure.in for a package by
1975 scanning its source code for commonly used nonportable functions,
1976 programs, and header files.
1977 * ifnames to list the symbols used in #if and #ifdef directives in a
1979 * autoupdate to update a configure.in to use the version 2 macro names.
1980 * autoreconf to recursively remake configure and configuration header
1981 files in a source tree.
1983 ** Changed utilities:
1984 * autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
1985 * autoconf and autoheader can look for package-local definition files
1986 in an alternate directory.
1989 * AC_CACHE_VAL to share results of tests between configure runs.
1990 * AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
1991 that macros invoked with AC_REQUIRE don't interrupt other macros.
1992 * AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
1993 support deciding unguessable features based on the host and target types.
1994 * AC_CONFIG_SUBDIRS to recursively configure a source tree.
1995 * AC_ARG_PROGRAM to use the options --program-prefix,
1996 --program-suffix, and --program-transform-name to change the names
1997 of programs being installed.
1998 * AC_PREFIX_DEFAULT to change the default installation prefix.
1999 * AC_TRY_COMPILE to compile a test program without linking it.
2000 * AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
2001 * AC_CHECK_LIB to check for a particular function and library.
2002 * AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
2003 whether or not the test succeeds. They obsolete AC_CHECKING and AC_VERBOSE.
2004 * AC_SUBST_FILE to insert one file into another.
2005 * AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
2006 * AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
2007 * AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
2008 * AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
2011 * Many macros renamed systematically, but old names are accepted for
2012 backward compatibility.
2013 * AC_OUTPUT adds the "automatically generated" comment to
2014 non-Makefiles where it finds @configure_input@ in an input file, to
2015 support files with various comment syntaxes.
2016 * AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
2017 files when they are not enclosed in @ signs.
2018 * AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
2019 override the file name "config.status".
2020 * AC_OUTPUT takes an optional argument for passing variables from
2021 configure to config.status.
2022 * AC_OUTPUT and AC_CONFIG_HEADER allow you to override the input-file names.
2023 * AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
2024 CPPFLAGS, and LDFLAGS from the environment.
2025 * AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
2026 * AC_PROG_INSTALL looks for install-sh or install.sh in the directory
2027 specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
2028 srcdir/../.. by default.
2029 * AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
2030 * AC_DEFINE no longer prints anything, because of the new result reporting
2031 mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
2032 * AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
2033 * AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
2034 --enable- and --with- options.
2035 * AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
2036 execute on success or failure.
2037 * Checking for C functions in C++ works.
2040 * AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
2041 better maintained with them.
2042 * AC_ARG_ARRAY removed because no one was likely using it.
2043 * AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
2044 take arguments, for consistency with all of the other specific checks.
2047 * Comes with config.sub and config.guess, and uses them optionally.
2048 * Uses config.cache to cache test results. An alternate cache file
2049 can be selected with the --cache-file=FILE option.
2050 * Uses optional shell scripts $prefix/share/config.site and
2051 $prefix/etc/config.site to perform site or system specific initializations.
2052 * configure saves compiler output to ./config.log for debugging.
2053 * New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
2054 * acsite.m4 is the new name for the system-wide aclocal.m4.
2055 * Has a DejaGnu test suite.
2057 Major changes in Autoconf 1.11:
2059 * AC_PROG_INSTALL calls install.sh with the -c option.
2060 * AC_SET_MAKE cleans up after itself.
2061 * AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
2062 * AC_OUTPUT prevents shells from looking in PATH for config.status.
2064 Plus a few other bug fixes.
2066 Major changes in Autoconf 1.10:
2068 * autoheader uses config.h.bot if present, analogous to config.h.top.
2069 * AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
2071 * AC_PROG_CXX looks for cxx as a C++ compiler.
2073 Plus several bugs fixed.
2075 Major changes in Autoconf 1.9:
2077 * AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
2078 * AC_SIZEOF_TYPE generates the cpp symbol name automatically,
2079 and autoheader generates entries for those names automatically.
2080 * AC_FIND_X gets the result from xmkmf correctly.
2081 * AC_FIND_X assumes no X if --without-x was given.
2082 * AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
2083 * AC_PROG_INSTALL finds OSF/1 installbsd.
2085 Major changes in Autoconf 1.8:
2088 * New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
2089 AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
2090 for checking both C++ and C features in one configure script.
2091 * New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
2092 * New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
2093 AC_SET_MAKE, AC_ENABLE.
2096 * AC_FIND_X looks for X in more places.
2097 * AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
2098 install.sh is distributed with Autoconf.
2099 * AC_DECLARE_YYTEXT has been removed because it can't work, pending
2100 a rewrite of quoting in AC_DEFINE.
2101 * AC_OUTPUT adds its comments in C format when substituting in C files.
2102 * AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
2104 ** New or changed command line options:
2105 * configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
2106 * configure accepts --without-PACKAGE, which sets withval=no.
2107 * configure accepts --x-includes=DIR and --x-libraries=DIR.
2108 * Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
2109 * configure accepts --help, --version, --silent/--quiet, --no-create options.
2110 * configure accepts and ignores most other Cygnus configure options, and
2111 warns about unknown options.
2112 * config.status accepts --help, --version options.
2114 ** File names and other changes:
2115 * Relative srcdir values are not made absolute.
2116 * The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
2117 * Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
2118 * autoheader optionally copies config.h.top to the beginning of config.h.in.
2119 * The example Makefile dependencies for configure et al. work better.
2120 * Namespace cleanup: all shell variables used internally by Autoconf
2121 have names beginning with `ac_'.
2123 More big improvements are in process for future releases, but have not
2124 yet been (variously) finished, integrated, tested, or documented enough
2127 Major changes in Autoconf 1.7:
2129 * New macro AC_OBSOLETE.
2130 * Bugs in Makefile.in fixed.
2131 * AC_LONG_FILE_NAMES improved.
2133 Major changes in Autoconf 1.6:
2135 * New macro AC_LONG_64_BITS.
2136 * Multiple .h files can be created.
2137 * AC_FIND_X looks for X files directly if it doesn't find xmkmf.
2138 * AC_ALLOCA defines C_ALLOCA if using alloca.c.
2139 * --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
2140 * Unused --no-create option to configure removed.
2141 * autoheader doesn't change the timestamp of its output file if
2142 the file didn't change.
2143 * All macros that look for libraries now use AC_HAVE_LIBRARY.
2144 * config.status checks three optional environment variables to
2145 modify its behavior.
2146 * The usual bug fixes.
2148 Major changes in Autoconf 1.5:
2150 * New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
2151 * autoconf and autoheader scripts have GNU standards conforming
2152 --version and --help options (they print their message and exit).
2155 Major changes in Autoconf 1.4:
2157 * New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
2158 AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
2159 * autoconf and autoheader use the M4 environment variable to determine the
2160 name of the M4 program to use.
2161 * The --macrodir option to autoconf and autoheader specifies the directory
2162 in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
2163 * autoconf and autoheader can take `-' as their file names, which means to
2164 read stdin as input.
2165 * Resulting configure scripts can take a --verbose option which causes them
2166 to print the results of their tests.
2167 * AC_DEFINE quotes its second argument in such a way that spaces, magic
2168 shell characters, etc. will be preserved during various stages of
2169 expansion done by the shell. If you don't want this, use
2170 AC_DEFINE_UNQUOTED instead.
2171 * Much textual processing done with external calls to tr and sed have been
2172 internalized with builtin M4 `patsubst' and `translit' calls.
2173 * AC_OUTPUT doesn't hardwire the file names it outputs. Instead, you can
2174 set the shell variables `gen_files' and `gen_config' to the list of
2175 file names to output.
2176 * AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
2177 "lex.yy" or "lexyy", depending on the system.
2178 * AC_PROGRAMS_CHECK takes an optional third arg. If given, it is used as
2180 * If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
2181 * AC_CONST works much more reliably on more systems.
2184 Major changes in Autoconf 1.3:
2186 configure no longer requires awk for packages that use a config.h.
2187 Support handling --with-PACKAGE options.
2188 New `autoheader' script to create `config.h.in' from `configure.in'.
2189 Ignore troublesome -lucb and -lPW when searching for alloca.
2190 Rename --exec_prefix to --exec-prefix for GNU standards conformance.
2191 Improve detection of STDC library.
2192 Add AC_HAVE_LIBRARY to check for non-default libraries.
2193 Function checking should work with future GNU libc releases.
2195 Major changes in Autoconf 1.2:
2197 The --srcdir option is now usually unnecessary.
2198 Add a file containing sample comments describing CPP macros.
2199 A comment in config.status tells which host it was configured on.
2200 Substituted variable values can now contain commas.
2201 Fix bugs in various feature checks.
2203 Major changes in Autoconf 1.1:
2205 Added AC_STRCOLL macro.
2206 Made AC_GETLOADAVG check for more things.
2207 AC_OUTPUT argument is now optional.
2212 Copyright (C) 1993-1996, 1998-2014 Free Software Foundation, Inc.
2214 Copying and distribution of this file, with or without modification,
2215 are permitted in any medium without royalty provided the copyright
2216 notice and this notice are preserved. This file is offered as-is,
2217 without warranty of any kind.