1 GNU Autoconf NEWS - User visible changes.
3 * Noteworthy changes in release ?.? (????-??-??) [?]
5 ** The use of the long-deprecated name 'configure.in' for the autoconf
6 input file now elicits a warning in the 'obsolete' category.
8 ** Older version of automake and aclocal (< 1.8) are no longer supported
11 ** Use of printf is now recommended instead of working around bugs in
12 echo. Macros AS_ECHO and AS_ECHO_N now expand unconditionally to
13 'printf "%s\n"' and 'printf %s'.
17 - New macro AC_C__GENERIC.
19 - AC_CONFIG_MACRO_DIRS
20 New macro, used to declare multiple directories when looking for
21 local M4 macros. This macro overcomes some of the shortfalls in the
22 older AC_CONFIG_MACRO_DIR, which could only be used once; although
23 the older macro remains for compatibility with older tools. The
24 newer macro will be used by the upcoming Automake 1.13 release to
25 eliminate the need to specify ACLOCAL_AMFLAGS in Makefile.am.
27 - AC_PROG_CC now prefers C11 if available, falling back on C99 and
28 then on C89 as before. Similarly, AC_PROG_CXX now prefers C++11
29 if available, falling back on C++98.
31 - AC_PROG_CC is now defined via AC_DEFUN_ONCE, to avoid bloat in 'configure'.
33 - AC_PROG_CC_STDC, AC_PROG_CC_C89, AC_PROG_CC_C99 have been marked as obsolete.
34 Applications should use AC_PROG_CC.
36 - AC_USE_SYSTEM_EXTENSIONS now enables more system extensions on HP-UX,
39 - AC_FUNC_VFORK now checks for the signal-handling bug in Solaris 2.4 'vfork'.
40 Formerly, it ignored this bug, so that Emacs could use some tricky
41 code on that platform. Solaris 2.4 has not been supported since
42 2003 and nowadays it's better to omit that old trick.
44 - Autotest provides a new macro AT_DATA_UNQUOTED, similar to AT_DATA
45 but processing variable substitutions, command substitutions and
46 backslashes in the contents argument.
48 - AC_CONFIG_TESTDIR will automatically pass EXEEXT to a testsuite (via
51 - AT_TESTED arguments can use variable or command substitutions, including
54 * Noteworthy changes in release 2.69 (2012-04-24) [stable]
56 ** Autoconf now requires perl 5.6 or better (but generated configure
57 scripts continue to run without perl).
59 * Noteworthy changes in release 2.68b (2012-03-01) [beta]
60 Released by Eric Blake, based on git versions 2.68.*.
62 ** Autoconf-generated configure scripts now unconditionally re-execute
63 themselves with $CONFIG_SHELL, if that's set in the environment.
65 ** The texinfo documentation no longer specifies "front-cover" or
66 "back-cover" texts, so that it may now be included in Debian's
69 ** Support for the Go programming language has been added. The new macro
70 AC_LANG_GO sets variables GOC and GOFLAGS.
72 ** AS_LITERAL_IF again treats '=' as a literal. Regression introduced in
75 ** The macro AS_EXECUTABLE_P, present since 2.50, is now documented.
79 - AC_PROG_LN_S and AS_LN_S now fall back on 'cp -pR' (not 'cp -p') if 'ln -s'
80 does not work. This works better for symlinks to directories.
82 - New macro AC_HEADER_CHECK_STDBOOL.
84 - New and updated macros for Fortran support:
86 AC_FC_CHECK_BOUNDS to enable array bounds checking
87 AC_F77_IMPLICIT_NONE and AC_FC_IMPLICIT_NONE to disable implicit integer
88 AC_FC_MODULE_EXTENSION to compute the Fortran 90 module name extension
89 AC_FC_MODULE_FLAG for the Fortran 90 module search path flag
90 AC_FC_MODULE_OUTPUT_FLAG for the Fortran 90 module output directory flag
91 AC_FC_PP_SRCEXT for preprocessed Fortran source files extensions
92 AC_FC_PP_DEFINE for the Fortran preprocessor define flag
94 * Noteworthy changes in release 2.68 (2010-09-22) [stable]
95 Released by Eric Blake, based on git versions 2.67.*.
97 ** AC_MSG_ERROR (and AS_ERROR) can once again be followed immediately by
98 `dnl'. Regression introduced in 2.66.
100 ** AC_INIT again allows URLs with '?' for its BUG-REPORT argument.
101 Regression introduced in 2.66.
103 ** AC_REPLACE_FUNCS again allows a non-literal argument, such as a shell
104 variable that expands to a list of functions to check. Regression
107 ** AT_BANNER() with empty argument will cause visual separation from previous
110 ** The macros AC_PREPROC_IFELSE, AC_COMPILE_IFELSE, AC_LINK_IFELSE, and
111 AC_RUN_IFELSE now warn if the first argument failed to use
112 AC_LANG_SOURCE or AC_LANG_PROGRAM to generate the conftest file
113 contents. A new macro AC_LANG_DEFINES_PROVIDED exists if you have
114 a compelling reason why you cannot use AC_LANG_SOURCE but must
117 ** The macro m4_define_default is now documented.
119 ** Symlinked config.cache files are supported; configure now tries to
120 update non-symlinked cache files atomically, so that concurrent configure
121 runs do not leave behind broken cache files. It is still unspecified
122 which subset or union of results is cached though.
124 ** Autotest testsuites should not contain long text lines any more, and be
125 portable even when very many test groups are used.
127 ** AT_CHECK semantics with respect to the Autotest variable $at_status and
128 shell execution environment of the arguments are documented now.
130 ** AC_FC_LIBRARY_LDFLAGS now tolerates output from newer gfortran.
132 ** Newly obsolete macros
133 The following macros have been marked obsolete. New programs
134 should use the corresponding Gnulib modules. Gnulib not only
135 detects a larger set of portability problems with these functions,
136 but also provides complete workarounds.
138 AC_FUNC_ERROR_AT_LINE AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK
139 AC_FUNC_MKTIME AC_FUNC_STRTOD
142 * Major changes in Autoconf 2.67 (2010-07-21) [stable]
143 Released by Eric Blake, based on git versions 2.66.*.
145 ** AC_CONFIG_SUBDIRS with more than one subdirectory at a time works again.
146 Regression introduced in 2.66.
148 ** AC_CHECK_SIZEOF of a pointer type works again. Regression introduced in
151 ** New macro AC_FC_LINE_LENGTH to accept long Fortran source code lines.
153 ** AC_PREPROC_IFELSE now keeps the preprocessed output in the conftest.i
154 file for inspection by the commands in the ACTION-IF-TRUE argument.
156 ** AC_INIT again allows parentheses and other characters that are literal
157 in single- or double-quoted strings, and in quoted and unquoted
158 here-documents, for its PACKAGE and VERSION arguments. Regression
161 ** autoreconf passes warning flags to new enough versions of aclocal.
163 ** Running an Autotest testsuite in parallel mode no longer triggers a
164 race condition that could cause the testsuite run to end early,
165 fixing a sporadic failure in autoconf's own testsuite. Bug present
166 since introduction of parallel tests in 2.63b.
169 * Major changes in Autoconf 2.66 (2010-07-02) [stable]
170 Released by Eric Blake, based on git versions 2.65.*.
172 ** AC_FUNC_MMAP works in C++ mode again. Regression introduced in 2.65.
174 ** Use of m4_divert without a named diversion now issues a syntax warning,
175 since it is seldom right to change diversions behind autoconf's back.
177 ** The macros AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, and
178 AC_TYPE_INT64_T work again. Regression introduced in 2.65.
180 ** AC_PROG_INSTALL correctly uses `shtool' again. Regression introduced
183 ** Autoconf should work on EBCDIC hosts.
185 ** AC_CHECK_DECL and AC_CHECK_DECLS accept optional function argument types
186 for overloaded C++ functions.
188 ** AS_SET_CATFILE accepts nonliterals in its variable name argument now.
190 ** Autotest testsuites accept an option --recheck to rerun tests that
191 failed or passed unexpectedly during the last non-debug testsuite run.
193 ** AC_ARG_ENABLE and AC_ARG_WITH now also accept `+' signs in `--enable-*'
194 and `--with-*' arguments, converting them to underscores for the variable
197 ** In configure scripts, loading CONFIG_SITE no longer searches PATH,
198 and problems in loading the configuration site files are diagnosed.
200 ** Autotest testsuites may optionally provide colored test results.
202 ** The previously undocumented Autotest macros AT_ARG_OPTION and
203 AT_ARG_OPTION_ARG have seen bug fixes and are documented now.
204 AT_ARG_OPTION has been changed in that the negative of a long option
205 --OPTION is now --no-OPTION rather than --noOPTION.
207 ** The macro AS_LITERAL_IF is slightly more conservative; text
208 containing shell quotes are no longer treated as literals.
209 Furthermore, a new macro, AS_LITERAL_WORD_IF, adds an additional
210 level of checking that no whitespace occurs in literals.
212 ** The macros AS_TR_SH and AS_TR_CPP no longer expand their results.
214 ** The following macros are now documented:
217 ** New macro AC_FC_FIXEDFORM to accept fixed-form Fortran.
220 * Major changes in Autoconf 2.65 (2009-11-21) [stable]
221 Released by Eric Blake, based on git versions 2.64.*.
223 ** Autoconf is now licensed under the General Public License version 3
224 or later (GPLv3+). As with earlier versions, the license includes
225 an exception clause so that you may release a configure script
226 generated by autoconf under the license of your own program.
228 ** New macros to support Objective C++.
229 AC_PROG_OBJCXX AC_PROG_OBJCXXCPP
231 ** The following undocumented autoconf macros, removed in Autoconf 2.64,
232 have been reinstated:
235 These macros are present only for backwards compatibility purposes.
237 ** The macro AC_LANG_COMPILER no longer fails on embedded systems that
238 lack fopen in the C library, such as AVR or RTEMS (regression
241 ** The AC_FC_FREEFORM macro no longer suffers from a whitespace bug that
242 made it fail with some Fortran compilers (regression introduced in
245 ** The AC_TYPE_UINT64_T and AC_TYPE_INT64_T macros have been fixed to no
246 longer mistakenly select a 32-bit type on some compilers (bug present
247 since macros were introduced in 2.59c).
249 ** The AC_FUNC_MMAP macro has been fixed to be portable to systems like
250 Cygwin (bug present since macro was introduced in 2.0).
252 ** The following documented autotest macros are new:
255 ** The following m4sugar macros now quote their expansion:
256 m4_toupper m4_tolower
258 ** The following m4sugar macros are new:
261 ** The m4sugar macro m4_text_wrap now copes with embedded quoting without
262 requiring quadrigraphs. For uses like AC_ARG_VAR([a], [[b c]]),
263 this gives the intuitive behavior of "[b c]" in the output (2.63
264 gave the output of "[b], [c]", and 2.64 encountered a failure).
266 ** The `$tmp' temporary directory used in config.status is documented for
269 ** config.status now provides a --config option to produce the configuration.
271 ** Many cache variables used by Autoconf's macros are now documented.
273 ** Configure scripts work better on DJGPP by avoiding a bug present in
274 the DJGPP port of bash 2.04 in handling 'return' in a shell
275 function (regression introduced in 2.64).
277 * Major changes in Autoconf 2.64 (2009-07-26) [stable]
278 Released by Eric Blake, based on git versions 2.63b.*.
280 ** Autoconf now requires GNU M4 1.4.6 or later. Earlier versions of M4
281 have a bug in regular expression handling that interferes with some
282 of the speedups provided since Autoconf 2.63. GNU M4 1.4.13 or
283 later is recommended.
285 ** AS_IF and AS_CASE have been taught to avoid syntax errors even when
286 given arguments that expand to just whitespace.
288 ** The following documented autoconf macros are new:
289 AC_ERLANG_SUBST_ERTS_VER
291 ** The autoheader tool now understands m4 macro arguments passed to
292 AC_DEFINE and AC_DEFINE_UNQUOTED.
294 ** Ensure AT_CHECK can support commands that include a # given with
295 proper m4 quoting. For shell comments, this is a new feature; for
296 non-shell comments, this fixes a regression introduced in 2.63b.
297 Additionally, AT_CHECK correctly supplies shell escapes for
298 metacharacters occurring in m4 macro expansions within the expected
299 stdout and stderr parameters.
301 ** The macro AT_CHECK now understands the concept of hard failure. If
302 a test exits with an unexpected status 99, cleanup actions for the
303 test are inhibited and the test is treated as a failure regardless
304 of AT_XFAIL_IF. It also understands the new directives
305 ignore-nolog, stdout-nolog, and stderr-nolog.
307 ** The following documented autotest macros are new:
308 AT_CHECK_UNQUOTED AT_FAIL_IF AT_SKIP_IF
310 ** The following documented m4sugar macros are new:
311 m4_argn m4_copy_force m4_default_nblank m4_default_nblank_quoted
312 m4_ifblank m4_ifnblank m4_rename_force
314 ** The autoconf testsuite now exercises all Erlang macros.
316 * Major changes in Autoconf 2.63b (2009-03-31) [beta]
317 Released by Eric Blake, based on git versions 2.63.*.
319 ** The manual is now shipped under the terms of the GNU FDL 1.3.
321 ** AC_REQUIRE now detects the case of an outer macro which first expands
322 then later indirectly requires the same inner macro. Previously,
323 this case led to silent out-of-order expansion (bug present since
324 2.50); it now issues a syntax warning, and duplicates the expansion
325 of the inner macro to guarantee dependencies have been met. See
326 the manual for advice on how to refactor macros in order to avoid
327 the bug in earlier autoconf versions and avoid increased script
328 size in the current version.
330 ** AC_DEFUN_ONCE has improved semantics. Previously, a macro declared
331 with AC_DEFUN_ONCE warned on a second invocation; and out-of-order
332 expansion was still possible. Now, dependencies are guaranteed,
333 and subsequent invocations are a silent no-op. This makes
334 AC_DEFUN_ONCE an ideal macro for silencing AC_REQUIRE warnings.
336 ** The following macros are now defined with AC_DEFUN_ONCE. This means
337 a subtle change in semantics; previously, an AC_DEFUN macro could
338 expand one of these macros multiple times or surround the macro
339 inside shell conditional text to bypass the effects of these
340 macros, but now the macro will expand exactly once, and prior to
341 the start of any enclosing AC_DEFUN macro:
342 AC_CANONICAL_BUILD AC_CANONICAL_HOST AC_CANONICAL_TARGET
343 AC_HEADER_ASSERT AC_PROG_INSTALL AC_PROG_MKDIR_P
344 AC_USE_SYSTEM_EXTENSIONS
346 ** AC_LANG_ERLANG works once again (regression introduced in 2.61a).
348 ** AC_HEADER_ASSERT is fixed so that './configure --enable-assert' no
349 longer mistakenly disables assertions.
351 ** AC_INIT now takes an optional fifth parameter that can be used to
352 set AC_PACKAGE_URL, a URL for the package's home page; the URL is
353 used in `configure --help' and is also available via AC_DEFINE.
355 ** Autotest testsuites accept an option --jobs[=N] for parallel testing.
356 This feature is still in testing, and may not work on every
357 platform, help in improving it would be appreciated.
359 ** Autotest testsuites do not attempt to write startup error messages
360 to the log file before that is opened (regression introduced in 2.63).
362 ** Configure scripts now use shell functions. This feature leads to
363 smaller configure files and faster execution.
365 ** Present But Cannot Be Compiled: Autoconf will now proceed with
366 the compiler's result if a header is present but cannot be compiled.
367 The warning is still printed, and you should really fix it by
368 providing a fourth parameter to AC_CHECK_HEADER/AC_CHECK_HEADERS.
370 ** Autoreconf added aclocal to the set of programs affected by the
371 `autoreconf -I dir' option.
373 ** The following documented m4sugar macros are new:
374 m4_chomp m4_chomp_all m4_cleardivert m4_curry m4_default_quoted
375 m4_esyscmd_s m4_map_args m4_map_args_pair m4_map_args_sep
376 m4_map_args_w m4_set_map m4_set_map_sep m4_stack_foreach
377 m4_stack_foreach_lifo m4_stack_foreach_sep
378 m4_stack_foreach_sep_lifo
380 ** The following m4sugar macros are documented now, but in some cases
381 with slightly different semantics than what the previous
382 undocumented version had:
383 m4_copy m4_dumpdefs m4_rename m4_version_prereq
385 ** The m4sugar macro m4_expand has been taught to handle unterminated
386 comments and shell case statements. As a result, it is used
387 internally in more places, such as AC_DEFINE and AT_CHECK. Most
388 uses of AC_DEFINE and AT_CHECK should not behave any differently;
389 however, it may be necessary to add double-quoting around
390 unbalanced `(' where single-quoting used to be sufficient.
392 ** The following documented m4sh macros are new:
393 AS_INIT_GENERATED AS_LINENO_PREPARE AS_ME_PREPARE AS_SET_STATUS
394 AS_VAR_APPEND AS_VAR_ARITH AS_VAR_COPY
396 ** The following m4sh macros are documented now, but in some cases
397 with slightly different semantics than what the previous
398 undocumented version had:
399 AS_ECHO AS_ECHO_N AS_ESCAPE AS_EXIT AS_LITERAL_IF AS_UNSET
400 AS_VAR_IF AS_VAR_POPDEF AS_VAR_PUSHDEF AS_VAR_SET AS_VAR_SET_IF
401 AS_VAR_TEST_SET AS_VERSION_COMPARE
403 ** The m4sh macros AS_IF and AS_CASE can now be used in shell lists.
404 The responsibility for supplying a trailing newline now belongs to
405 the call site, but since most users did not add dnl, this generally
406 results in fewer empty lines in configure.
409 * Major changes in Autoconf 2.63 (2008-09-09) [stable]
410 Released by Eric Blake, based on git versions 2.62.*.
412 ** AC_C_BIGENDIAN does not mistakenly report "universal" for some
413 bigendian hosts, a regression introduced with universal binary
416 ** AC_PATH_X now includes /lib64 and /usr/lib64 in its list of default
419 ** AC_USE_SYSTEM_EXTENSIONS no longer conflicts with an external
420 AC_DEFINE([__EXTENSIONS__]). This fixes a regression introduced in
421 2.62 when using macros such as AC_AIX that were made obsolete in
422 favor of the more portable AC_USE_SYSTEM_EXTENSIONS.
424 ** AC_CHECK_TARGET_TOOLS is usable in the non-cross-compile case.
426 ** Newly obsolete macros
427 The following macro has been marked obsolete, since current porting
428 targets can safely assume C89 semantics that signal handlers return
429 void. We have no current plans to remove the macro.
433 ** The macros m4_map and m4_map_sep now ignore any list elements
434 consisting of just empty quotes, and m4_map_sep now expands its
435 separator. This fixes a regression in 2.62 when these macros were
436 first documented, for the sake of clients expecting the semantics
437 that these macros had prior to that time. The new macros m4_mapall
438 and m4_mapall_sep, along with extra quoting of the separator, can
439 be used to get the semantics that m4_map_sep had in 2.62.
441 ** Clients of m4_expand, such as AS_HELP_STRING and AT_SETUP, can now
442 handle properly quoted but otherwise unbalanced parentheses (for
443 some macros, this fixes a regression in 2.62).
445 ** Two new quadrigraphs have been introduced: @{:@ for (, and @:}@ for ),
446 allowing the output of unbalanced parentheses in more contexts.
448 ** The following m4sugar macros are new:
449 m4_cleardivert m4_joinall m4_mapall m4_mapall_sep m4_reverse
450 m4_set_add m4_set_add_all m4_set_contains m4_set_contents
451 m4_set_delete m4_set_difference m4_set_dump m4_set_empty
452 m4_set_foreach m4_set_intersection m4_set_list m4_set_listc
453 m4_set_remove m4_set_size m4_set_union
455 ** The following m4sugar macros now accept multiple arguments, as is the
456 case with underlying m4:
457 m4_defn m4_popdef m4_undefine
459 ** The following m4sugar macros now guarantee linear scaling; they
460 previously had linear scaling with m4 1.6 but quadratic scaling
461 when using m4 1.4.x. All macros built on top of these also gain
462 the scaling improvements.
463 m4_bmatch m4_bpatsubsts m4_case m4_cond m4_do m4_dquote_elt
464 m4_foreach m4_join m4_list_cmp m4_map m4_map_sep m4_max
467 ** AT_KEYWORDS once again performs expansion on its argument, such that
468 AT_KEYWORDS([m4_if([$1], [], [default])]) no longer complains about
469 the possibly unexpanded m4_if [regression introduced in 2.62].
471 ** Config header templates `#undef UNDEFINED /* comment */' do not lead to
472 nested comments any more; regression introduced in 2.62.
475 * Major changes in Autoconf 2.62 (2008-04-05) [stable]
476 Released by Eric Blake, based on git versions 2.61a.*.
478 ** Many optimizations have been applied to make overall execution faster.
480 ** Autotest now makes use of shell functions.
482 ** config.status now uses awk instead of sed also for config headers.
484 - As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
485 values, i.e., backslash-newline combinations are handled correctly.
486 Further, for config headers, the total size of values is not limited by
487 the POSIX length limit of text lines any more, only each single line.
489 ** New config variable `top_build_prefix'.
491 ** New Autoconf macros:
492 AC_AUTOCONF_VERSION AC_OPENMP AC_PATH_PROGS_FEATURE_CHECK
494 ** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.
496 ** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
497 like '__restrict' if the variant spelling is available, as this is
498 more likely to work when mixing C and C++ code.
500 ** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
501 be a string of tokens such that "T y;" is a valid member declaration
504 ** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
505 is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.
507 ** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
508 they did not work for function types. In C++, they now work on any
509 type-id that can be the operand of sizeof; this is similar to C,
510 except it excludes anonymous struct and union types. Formerly,
511 some (but not all) C++ types involving anonymous struct and union
512 were accepted, though this was not documented.
514 ** AC_CONFIG_LINKS now prefers to link against files in the build tree
515 if found, and it works to link against a file of the same name in
516 the source tree, even if both trees coincide.
518 ** AC_INIT no longer alters $@; regression introduced in 2.60.
520 ** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.
522 ** AS_HELP_STRING no longer underquotes its first argument; it also handles
523 the case where the first argument contains single-quoted commas.
524 For example, "AS_HELP_STRING([-a, [--arg[=foo]]], [bar])" produces:
525 " -a, --arg[=foo] bar"
526 Additionally, the macro now takes two additional arguments,
527 indent-column and wrap-column; these should not normally be needed,
528 but can be used to fine-tune how the output text is wrapped.
530 ** AC_PROG_INSTALL now requires an install program that can install multiple
531 files into a target directory.
533 ** The command 'autoconf -' now correctly processes a file from stdin.
535 ** 'autoreconf -m' now honors $MAKE.
537 ** For all of the directory arguments for 'configure', such as '--prefix'
538 or '--bindir', trailing slashes are stripped. As an example, if
539 tab completion in the user's shell appends trailing slashes, the
540 command './configure --prefix=/usr/' will still result in an
541 expanded libdir value of /usr/lib, not /usr//lib.
543 ** `configure --help=recursive' now works in read-only trees and from
544 unconfigured build trees.
546 ** If precious variables differ only in whitespace, then the cache consistency
547 check warns instead of fails, and reuses the old value.
549 ** AT_BANNER is now documented.
551 ** AT_SETUP now handles macro expansions properly when calculating line
554 ** Autotest now determines $srcdir correctly.
556 ** Testsuites built by autotest now accept a -C/--directory=DIR option
557 to adjust the working directory prior to creating files.
559 ** Autoconf now requires GNU M4 1.4.5 or later. Earlier versions of M4 have
560 a bug in macro tracing that interferes with the interaction between
561 Autoconf and Automake. GNU M4 1.4.11 or later is recommended. The
562 configure search for a working M4 is improved.
564 ** For portability with the eventual M4 2.0, macros should no longer use
565 anything larger than $9 to refer to arguments.
567 ** Documentation for m4sugar is improved.
569 - The following macros were previously available as undocumented
570 interfaces; the macros are now documented as stable interfaces.
572 __oline__ m4_assert m4_bmatch m4_bpatsubsts m4_car m4_case
573 m4_cdr m4_default m4_divert_once m4_divert_pop m4_divert_push
574 m4_divert_text m4_do m4_errprintn m4_fatal m4_flatten
575 m4_ifndef m4_ifset m4_ifval m4_ifvaln m4_location
576 m4_n m4_shiftn m4_strip m4_warn
578 - The following macros were previously available as undocumented
579 interfaces, but had bug fixes or semantic changes as part of this
580 release. Packages that relied on the undocumented behavior
581 should be analyzed to make sure they will still work with the
582 new documented behavior.
584 m4_cmp m4_list_cmp m4_join m4_map m4_map_sep m4_sign
585 m4_text_box m4_text_wrap m4_version_compare
587 - The m4_wrap macro used to have unspecified order, but now
588 guarantees FIFO order. m4_wrap_lifo was added to guarantee LIFO
591 - Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
592 should consider using the new AC_AUTOCONF_VERSION instead.
594 - m4sugar macros that are not documented in the manual are still
595 deemed experimental, and should not be used outside of Autoconf.
597 ** The m4sugar macros m4_append and m4_append_uniq, first documented in
598 2.60, have been fixed to treat both the string and the separator
599 arguments consistently with regards to quoting. Prior to this fix,
600 m4_append_uniq could mistakenly duplicate entries if the expansion
601 of the separator resulted in a different string (for example, if it
602 contained quotes, a comma, or a macro name). However, it means
603 that programs previously using
604 m4_append([name], [string], [[, ]])
605 are now using a four-character separator instead of the intended
606 comma and space. If you need portability to earlier versions of
607 Autoconf, you can insert the following snippet after AC_INIT but
608 before any other macro expansions, to enforce the new semantics:
609 m4_pushdef([m4_append], [m4_define([$1],
610 m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
611 Additionally, m4_append_uniq now takes optional parameters that can
612 be used to take action depending on whether anything was appended,
613 and warns if a non-empty separator occurs within the string being
614 appended, since that can lead to duplicates.
616 ** The following m4sugar macros are new:
617 m4_append_uniq_w m4_apply m4_combine m4_cond m4_count
618 m4_dquote_elt m4_echo m4_expand m4_ignore m4_make_list m4_max
619 m4_min m4_newline m4_shift2 m4_shift3 m4_unquote m4_wrap_lifo
621 ** Warnings are now generated by default when an installer invokes
622 'configure' with an unknown --enable-* or --with-* option.
623 These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
624 macro, or by invoking 'configure' with --disable-option-checking.
626 ** Existing obsolete macros
627 The documentation for the following macros is adjusted to make it
628 more clear that they have previously been marked obsolete, as their
629 functionality can be accomplished by other macros. We have no
630 current plans to remove them from Autoconf.
632 AC_ENABLE AC_STRUCT_ST_BLKSIZE AC_STRUCT_ST_RDEV AC_WITH
634 ** Newly obsolete macros
635 The following macros have been marked obsolete, as they only
636 perform a subset of AC_USE_SYSTEM_EXTENSIONS. We have no current
637 plans to remove them.
639 AC_AIX AC_GNU_SOURCE AC_ISC_POSIX AC_MINIX
641 ** AC_C_LONG_DOUBLE is obsolescent.
642 The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
643 tests for problems that are so old that it is no longer of
644 practical importance on current systems. New programs need not use
645 AC_C_LONG_DOUBLE. We have no current plans to remove it.
647 ** AC_DIAGNOSE, AC_WARNING, and AC_FATAL are obsolescent.
648 The documentation now favors the use of M4sugar macros m4_warn and
649 m4_fatal, since the naming makes it more obvious that the
650 diagnostics are associated with M4 expansion (ie. when running
651 `autoconf'), and offers less confusion with the AC_MSG_ERROR,
652 AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
653 when running `configure'. We have no current plans to remove these
657 * Major changes in Autoconf 2.61a (2006-12-11)
659 ** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
660 on many platforms. This has been fixed.
662 ** AC_FUNC_SETVBUF_REVERSED is now obsolete. It is still defined for backward
663 compatibility but it does nothing. The macro was already
664 obsolescent, as the last systems to have the problem were those
665 based on SVR2, which became obsolete in 1987. The macro had bugs
666 on some modern systems and could no longer be maintained reliably
667 due to lack of ancient systems to test it on.
669 ** config.status now uses awk instead of sed for most substitutions, for speed.
671 - As a side effect multi-line values of substituted variables no
672 longer have a small limit in total size, though for portability
673 each line should not exceed the POSIX length limit for text lines.
675 - It is now documented that Makefile.in should not contain
676 overlapping variable occurrences, e.g., @VAR1@VAR2@.
677 Autoconf's behavior was always iffy in such cases, and the
678 awk implementation has changed the behavior.
680 ** Many uses of 'echo' have been rewritten so that Autoconf-generated
681 scripts have fewer problems with strings or file names containing
682 embedded special characters such as backslash or leading "-". This
683 was implemented by using `printf '%s\n' "$foo"' instead of `echo
684 "$foo"' when printf works. Due to the implementation technique
685 used, Autoconf-generated scripts now run considerably more slowly
686 on ancient implementations lacking printf. However, this should
687 not be a problem, since Autoconf-generated scripts in practice
688 invariably find a more-modern shell these days.
691 * Major changes in Autoconf 2.61 (2006-11-17)
693 ** New macros AC_C_FLEXIBLE_ARRAY_MEMBER, AC_C_VARARRAYS.
695 ** AC_ARG_ENABLE and AC_ARG_WITH now allow '.' in feature and package names.
698 * Major changes in Autoconf 2.60b (2006-10-22)
701 Autoconf-generated shell scripts no longer export BIN_SH, due to
702 configuration hassles with this. Installers who need BIN_SH in
703 their environment should set it before invoking 'configure' and
704 'make'. As far as we know, this affects only Unixware installations.
706 ** Obsolescent macros
707 The documentation now says that the following macros are obsolescent,
708 as they are superseded by Gnulib:
710 AC_FUNC_FNMATCH AC_FUNC_FNMATCH_GNU AC_FUNC_GETLOADVG AC_REPLACE_FNMATCH
712 New programs should use the Gnulib counterparts of these macros.
713 We have no current plans to remove them from Autoconf.
715 ** AC_COMPUTE_INT no longer caches or reports results.
717 ** AC_CHECK_DECL now also works with aggregate objects.
719 ** AC_USE_SYSTEM_EXTENSIONS now defines _TANDEM_SOURCE for NonStop platforms.
721 ** GNU M4 1.4.7 or later is now recommended.
724 New M4sugar macro, which is more secure than the POSIX M4 maketemp.
727 Now an alias for m4_mkstemp.
729 * Major changes in Autoconf 2.60a (2006-08-25)
731 ** GNU M4 1.4.6 or later is now recommended.
733 ** The check for C99 now tests for varargs macros, as documented.
734 It also tests that the preprocessor supports 64-bit integers.
736 ** Autoconf now uses constructs like "#ifdef HAVE_STDLIB_H" rather than
737 "#if HAVE_STDLIB_H", so that it now works with "gcc -Wundef -Werror".
739 ** The functionality of the undocumented _AC_COMPUTE_INT is now provided
740 by a public and documented macro, AC_COMPUTE_INT. The parameters to the
741 two macros are different, so autoupdate will not change the old private name
742 to the new one. _AC_COMPUTE_INT may be removed in a future release.
744 ** AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT now require
745 that long long types be at least 64 bits wide, as C99 and tradition
746 requires. Formerly, they accepted implementations of any width.
749 * Major changes in Autoconf 2.60
751 Released 2006-06-23, by Ralf Wildenhues.
753 ** Autoconf no longer depends on whether m4wrap is FIFO (as Posix requires)
754 or LIFO (as in GNU M4 1.4.x). GNU M4 2.0 is expected to conform to Posix
755 here, so m4wrap/m4_wrap users should no longer depend on LIFO behavior.
757 ** Provide a way to turn off warnings about the changed directory variables.
759 * Major changes in Autoconf 2.59d
761 Released 2006-06-05, by Ralf Wildenhues.
763 ** GNU make now recommended for VPATH builds
764 INSTALL now suggests VPATH builds (e.g., "sh ../srcdir/configure")
765 only if you use GNU make. In practice, other 'make' implementations
766 have too many subtle incompatibilities in their support for VPATH.
767 Many packages (including Autoconf itself) are portable to other
768 'make' implementations, but some packages are not, and recommending
769 GNU make keeps the installation instructions simpler.
771 ** Even more safety checks for the new Directory variables:
772 Warn about suspicious `${datarootdir}' found in config files output.
774 ** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
775 These never-documented macros and variables have been marked with
776 comments saying that they may be removed in a future release,
777 because their use can lead to unintended code being executed.
778 If you need functionality that only these macros or variables
779 currently supply, please write bug-autoconf@gnu.org.
781 ** AC_SUBST, AC_DEFINE
782 Literal arguments to these are passed to m4_pattern_allow now.
785 Passing 'ac_cv_prog_cc_stdc=no' to 'configure' now sets ac_cv_prog_cc_c99
786 and ac_cv_prog_cc_c89 to 'no' as well, for backward compatibility with
787 obsolete K&R tests in the Automake test suite.
796 Now more robust with special characters in file names, or when
797 multiple processes create the same directory at the same time.
799 ** Obsolescent macros
800 The documentation now says that the following macros are obsolescent:
801 they test for problems that are so old that they are no longer of
802 practical importance on current systems.
804 AC_C_BACKSLASH_A AC_FUNC_MEMCMP AC_HEADER_DIRENT
805 AC_C_CONST AC_FUNC_SELECT_ARGTYPES AC_HEADER_STAT
806 AC_C_PROTOTYPES AC_FUNC_SETPGRP AC_HEADER_STDC
807 AC_C_STRINGIZE AC_FUNC_SETVBUF_REVERSED AC_HEADER_SYS_WAIT
808 AC_C_VOLATILE AC_FUNC_STAT AC_HEADER_TIME
809 AC_FUNC_CLOSEDIR_VOID AC_FUNC_STRFTIME AC_ISC_POSIX
810 AC_FUNC_GETPGRP AC_FUNC_UTIME_NULL AC_PROG_GCC_TRADITIONAL
811 AC_FUNC_LSTAT AC_FUNC_VPRINTF AC_STRUCT_TM
813 New programs need not use these macros. We have no current plans to
817 For compatibility with future Libtool 2.0, autoreconf will invoke
818 libtoolize with the option `--ltdl' now, if LT_CONFIG_LTDL_DIR is
821 * Major changes in Autoconf 2.59c
823 Released 2006-04-12, by Ralf Wildenhues.
825 ** The configure command now redirects standard input from /dev/null,
826 to help avoid problems with subsidiary commands that might mistakenly
827 read standard input. AS_ORIGINAL_STDIN_FD points to the original
828 standard input before this redirection, if you really want configure to
829 read from standard input.
831 ** Directory variables adjusted to recent changes in the GNU Coding Standards.
832 The following directory variables are new:
834 datarootdir read-only architecture-independent data root [PREFIX/share]
835 localedir locale-specific message catalogs [DATAROOTDIR/locale]
836 docdir documentation root [DATAROOTDIR/doc/PACKAGE]
837 htmldir html documentation [DOCDIR]
838 dvidir dvi documentation [DOCDIR]
839 pdfdir pdf documentation [DOCDIR]
840 psdir ps documentation [DOCDIR]
842 The following variables have new default values:
844 datadir read-only architecture-independent data [DATAROOTDIR]
845 infodir info documentation [DATAROOTDIR/info]
846 mandir man documentation [DATAROOTDIR/man]
848 This means that if you use any of `@datadir@', `@infodir@', or
849 `@mandir@' in a file, you will have to ensure `${datarootdir}' is
850 defined in this file. As a temporary measure, if any of those are
851 found but no mention of `datarootdir', the substitutions will be
852 replaced with values that do not contain `${datarootdir}', and a
853 warning will be issued.
855 ** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
856 a trailing slash. Similar change will be made to ac_top_builddir in a
857 future release; the old style value, which matches (../)*, is (and will
858 continue to be) available as ac_top_build_prefix.
861 New macro to check for support of 'typeof' syntax a la GNU C.
863 ** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
864 New "once-only" variants of commonly-used macros, to make 'configure'
865 smaller and faster in common cases.
868 New macro to check for strtold with C99 semantics.
871 New macro that lets builder disable assertions at 'configure'-time.
874 Now checks for X11/Xlib.h and XrmInitialize (X proper) rather than
875 X11/Intrinsic.h and XtMalloc (Xt).
877 ** AC_PRESERVE_HELP_ORDER
878 New macro that causes `configure' to display help strings for AC_ARG_ENABLE
879 and AC_ARG_WITH arguments in one region, in the order defined. The default
880 behavior is to group options of each classes separately.
882 ** AC_PROG_CC, AC_PROG_CXX
883 No longer automatically arrange to declare the 'exit' function of C,
884 when a C++ compiler is used. Standard Autoconf macros no longer use
885 'exit', so this is no longer an issue for them. If you use C++, and
886 want to call 'exit', you'll have to arrange for its declaration
887 yourself. But we now suggest you return from 'main' instead.
889 ** AC_PROG_CC_C89, AC_PROG_CC_C99
890 New macros for ISO C99 support. AC_PROG_CC_C89 and AC_PROG_CC_C99
891 check for ANSI C89 and ISO C99 support respectively.
894 Has been unobsoleted, and will check if the compiler supports ISO
895 C99, falling back to ANSI C89 if not. ac_cv_prog_cc_stdc is
896 retained for backwards compatibility, assuming the value of
897 ac_cv_prog_cc_c99 or ac_cv_prog_cc_c89 (whichever is valid, in
900 ** AC_STRUCT_DIRENT_D_INO, AC_STRUCT_DIRENT_D_TYPE
901 New macros for checking commonly-used members of struct dirent.
904 The substituted value can now contain newlines.
907 The substitution now occurs only when @variable@ is on a line by itself,
908 optionally surrounded by spaces and tabs. The whole line is replaced.
910 ** AC_TYPE_LONG_DOUBLE, AC_TYPE_LONG_DOUBLE_WIDER
911 New macros to check for long double, and whether it is wider than double.
912 The old macro AC_C_TYPE_LONG_DOUBLE has been marked as obsolete;
913 applications should switch to the new macro.
915 ** AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, AC_TYPE_INT64_T,
916 AC_TYPE_INTMAX_T, AC_TYPE_INTPTR_T, AC_TYPE_LONG_LONG_INT, AC_TYPE_SSIZE_T,
917 AC_TYPE_UINT8_T, AC_TYPE_UINT16_T, AC_TYPE_UINT32_T, AC_TYPE_UINT64_T,
918 AC_TYPE_UINTMAX_T, AC_TYPE_UINTPTR_T, AC_TYPE_UNSIGNED_LONG_LONG_INT
919 New macros to check for C99 and POSIX types.
921 ** AC_USE_SYSTEM_EXTENSIONS
922 New macro to enable extensions to Posix.
925 New macro which is defined to the name of the first declared config header
926 or undefined if no config headers have been declared yet.
929 The macro correctly handles quadrigraphs now.
931 ** AS_BOURNE_COMPATIBLE, AS_SHELL_SANITIZE, AS_CASE
932 These macros are new or published now.
935 New macro for copyright notices in testsuite files.
937 ** ALLOCA, LIBOBJS, LTLIBOBJS
938 Object names added to these variables are now prefixed with `${LIBOBJDIR}',
939 as in `${LIBOBJDIR}alloca.o'. LIBOBJDIR is meant to be defined from
940 `Makefile.in' in case the object files lie in a different directory.
941 The LIBOBJDIR feature is experimental.
944 Supports --no-recursive now.
946 ** New macros to support Erlang/OTP.
947 New macros for configuring paths to Erlang tools and libraries:
948 AC_ERLANG_PATH_ERLC, AC_ERLANG_NEED_ERLC, AC_ERLANG_PATH_ERL,
949 AC_ERLANG_NEED_ERL, AC_ERLANG_CHECK_LIB, AC_ERLANG_SUBST_ROOT_DIR,
950 AC_ERLANG_SUBST_LIB_DIR.
952 New macros for configuring installation of Erlang libraries:
953 AC_ERLANG_SUBST_INSTALL_LIB_DIR, AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR.
955 ** The manual now mentions Gnulib more prominently.
957 ** New macros to support Objective C.
958 AC_PROG_OBJC, AC_PROG_OBJCPP.
960 * Major changes in Autoconf 2.59b
962 Released 2004-08-20, by Paul Eggert.
965 New macro that computes the default alignment of a type.
967 ** AC_CHECK_TOOL, AC_PATH_TOOL, AC_CHECK_TOOLS
968 When cross-compiling, these macros will give a warning if the tool
969 is not prefixed. In the future, unprefixed cross tools will not
970 be detected; please consult the info documentation for information
971 about the reason of this change.
973 ** AC_CHECK_TARGET_TOOL, AC_PATH_TARGET_TOOL, AC_CHECK_TARGET_TOOLS
974 New macros that detect programs whose name is prefixed with the
975 target type, if the build type and target type are different.
977 ** AC_REQUIRE_AUX_FILE
978 New trace macro that declares expected auxiliary files.
981 New macro that tests for a grep program that accepts as a long a line
984 ** AC_PROG_EGREP, AC_PROG_FGREP
985 These macros now require AC_PROG_GREP, and try EGREP="$GREP -E" and
986 FGREP="$GREP -F" respectively if possible, or else run a path search for
987 a program that accepts as long a line as possible.
990 New macro that tests for a sed program that truncates as few characters
993 * Major changes in Autoconf 2.59
995 Released 2003-11-04, by Akim Demaille
997 ** ac_abs_builddir etc.
998 Absolute file names were actually relative in 2.58.
1000 * Major changes in Autoconf 2.58
1002 Released 2003-11-04, by Akim Demaille
1005 core.* files are no longer removed, as they may be valid user files.
1007 ** autoreconf and auxiliary directory
1008 Autoreconf creates the auxiliary directory if needed. This is
1009 especially useful for initial "bootstrapping" of fresh CVS checkouts.
1011 ** AC_CONFIG_MACRO_DIR
1012 Use this macro to declare the directory for local M4 macros for aclocal.
1015 No longer includes twice the same file in LIBOBJS if invoked
1018 ** AC_CONFIG_COMMANDS
1019 The directory for its first argument is automatically created. For
1022 AC_CONFIG_COMMANDS([src/modules.hh], [...])
1024 $top_builddir/src/ is created if needed.
1026 ** Autotest and local.at
1027 The optional file local.at is always included in Autotest test suites.
1030 The warnings are always issued, including with cached runs.
1031 This became a significant problem since aclocal and automake can
1032 run autoconf behind the scene.
1034 ** autoheader warnings
1035 The warnings of autoheader can be turned off, using --warning.
1036 For instance, -Wno-obsolete disables the complaints about acconfig.h
1037 and other deprecated constructs.
1040 AC_C_RESTRICT, AC_INCLUDES_DEFAULT, AC_LANG_ASSERT, AC_LANG_WERROR,
1043 ** AC_DECL_SYS_SIGLIST
1047 Now checks that mktime is the inverse of localtime.
1049 ** Improve DJGPP portability
1050 The Autoconf tools and configure behave better under DJGPP.
1052 ** Present But Cannot Be Compiled
1053 New FAQ section dedicated to the mystic
1055 configure: WARNING: pi.h: present but cannot be compiled
1056 configure: WARNING: pi.h: check for missing prerequisite headers?
1057 configure: WARNING: pi.h: proceeding with the preprocessor's result
1060 ** Concurrent executions of autom4te
1061 autom4te now locks its internal files, which enables concurrent
1062 executions of autom4te, likely to happen if automake, autoconf,
1063 autoheader etc. are run simultaneously.
1066 Use of Libtool 1.5 and higher is encouraged. Compatibility with
1067 Libtool pre-1.4 is not checked.
1070 Testsuites no longer rerun failed tests in verbose mode; instead,
1071 failures are logged while the test is run.
1073 In addition, expected failures can be marked as such.
1075 * Major changes in Autoconf 2.57
1077 Released 2002-12-03 by Paul Eggert.
1079 Bug fixes for problems with AIX linker, with freestanding C compilers,
1080 with GNU M4 limitations, and with obsolete copies of GNU documents.
1082 The Free Documentation License has been upgraded from 1.1 to 1.2.
1084 * Major changes in Autoconf 2.56
1086 Released 2002-11-15 by Akim Demaille.
1088 One packaging problem fixed (config/install-sh was not executable).
1090 * Major changes in Autoconf 2.55
1092 Released 2002-11-14 by Akim Demaille.
1096 Have your configure.ac checked by autoscan ("autoscan").
1097 Try the warning options ("autoreconf -fv -Wall").
1101 - AC_CHECK_HEADER, AC_CHECK_HEADERS
1102 More information on proper use.
1104 - Writing Test Programs
1106 This sections explains how to write good test sources to use with
1107 AC_COMPILE_IFELSE etc. It documents AC_LANG_PROGRAM and so forth.
1109 - AC_FOO_IFELSE vs. AC_TRY_FOO
1111 Explains why Autoconf moves from AC_TRY_COMPILE etc. to
1112 AC_COMPILE_IFELSE and AC_LANG_PROGRAM etc.
1116 - Is more robust to different Gettext installations.
1118 - Produces messages (when --verbose) to be understood by Emacs'
1121 - Supports -W/--warnings.
1124 Once the GNU Build System reinstalled, run `./config.status
1125 --recheck && ./config.status && make' if possible.
1129 - Supports --cache, and --no-cache.
1131 - ~/.autom4te.cfg makes it possible to disable the caching mechanism
1132 (autom4te.cache). See `Customizing autom4te' in the documentation.
1139 Support for the obsoleted options -m, --macrodir, -l, --localdir is
1140 dropped in favor of the safer --include/--prepend-include scheme.
1145 AC_COMPILER_IFELSE, AC_FUNC_MBRTOWC, AC_HEADER_STDBOOL,
1146 AC_LANG_CONFTEST, AC_LANG_SOURCE, AC_LANG_PROGRAM, AC_LANG_CALL,
1147 AC_LANG_FUNC_TRY_LINK, AC_MSG_FAILURE, AC_PREPROC_IFELSE.
1150 Obsoleted macros are kept for Autoconf backward compatibility, but
1151 should be avoided in configure.ac. Running autoupdate is advised.
1152 AC_DECL_SYS_SIGLIST.
1154 - AC_DEFINE/AC_DEFINE_UNQUOTED
1156 We have to stop using the old compatibility scheme --that tried to
1157 avoid useless backslashes-- because Libtool 1.4.3 contains a
1159 AC_DEFINE([error_t], [int],
1160 [Define to a type to use for \`error_t' if it is not
1161 otherwise available.])
1163 We have to quote the single quotes and backslashes with \. The old
1164 compatibility scheme saw that ` was backslashed, and therefore did
1165 not quote the single quote... Failure. Hence, Autoconf 2.54 is not
1166 compatible with Libtool. Autoconf 2.55 is, but in some cases might
1167 produce more \ than wanted.
1169 Please, note that in the future the same problem will happen with
1170 AC_MSG_*: use `autoreconf -f -Wall'.
1174 - Portability of the Autoconf package to Solaris.
1176 - Spurious warnings caused by config.status.
1177 This bug is benign, but painful: on some systems (typically
1178 FreeBSD), warnings such as:
1180 config.status: creating Makefile
1181 mv: Makefile: set owner/group (was: 1357/0): Operation not permitted
1183 could be issued. This is fixed.
1186 Simultaneous executions of config.status are possible again.
1188 - Precious variables accumulation
1190 config.status could stack several copies of the precious variables
1194 ** Plans for later versions
1196 - ./configure <host>
1198 The compatibility hooks with the old scheme will be completely
1199 removed. Please, advice/use `--build', `--host', and `--target'
1202 - AC_CHECK_HEADER, AC_CHECK_HEADERS
1204 The tests will be stricter, please make sure your invocations are
1209 Shell functions will gradually be introduced, probably starting with
1210 Autotest. If you know machines which are in use that you suspect
1211 *not* to support shell functions, please run the test suite of
1212 Autoconf 2.55 on it, and report the results to
1213 bug-autoconf@gnu.org.
1217 Special characters in AC_MSG_* need not be quoted. Currently,
1218 Autoconf has heuristics to decide when a string is escaped, or has
1219 to be escaped. This scheme is fragile, and will be removed; the
1220 only risk is uglified messages. Please, run `autoreconf -f -Wall'
1221 to find occurrences that will be affected.
1223 * Major changes in Autoconf 2.54
1225 Released 2002-09-13 by Akim Demaille.
1229 - autoreconf no longer changes the version of the gettext/po/intl
1230 support files. It now adds the files the correspond to the
1231 AM_GNU_GETTEXT_VERSION declared in configure.ac.
1233 Warning: It now relies on the 'autopoint' program, which is part
1234 of GNU gettext 0.11.4 and newer.
1236 Please note that you need to have a GNU gettext version that
1237 corresponds at least to the AM_GNU_GETTEXT_VERSION declared
1238 in configure.ac. You can upgrade to newer GNU gettext versions,
1239 though, without needing to change configure.ac.
1241 - The -I DIR or --include=DIR option now appends DIR to the include path
1242 instead of prepending; this is for consistency with other GNU tools.
1243 The new -B DIR or --prepend-include=DIR option has the old behavior.
1248 Now handles all the gory details about LIBOBJS and LTLIBOBJS.
1249 Please, remove lines such as
1251 # This is necessary so that .o files in LIBOBJS are also
1252 # built via the ANSI2KNR-filtering rules.
1253 LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
1255 and read the `AC_LIBOBJ vs LIBOBJS' section. Do not define U in
1256 your Makefiles either.
1258 - AC_CONFIG_LINKS now makes copies if it can't make links.
1260 - AC_FUNC_FNMATCH now tests only for POSIX compatibility, reverting to
1261 Autoconf 2.13 behavior. The new macro AC_FUNC_FNMATCH_GNU also
1262 tests for GNU extensions to fnmatch, and replaces fnmatch if needed.
1264 - AC_FUNC_SETVBUF_REVERSED no longer fails when cross-compiling.
1266 - AC_PROG_CC_STDC is integrated into AC_PROG_CC.
1268 - AC_PROG_F77 default search no longer includes cf77 and cfg77.
1272 AC_C_BACKSLASH_A, AC_CONFIG_LIBOBJ_DIR, AC_GNU_SOURCE,
1273 AC_PROG_EGREP, AC_PROG_FGREP, AC_REPLACE_FNMATCH,
1274 AC_FUNC_FNMATCH_GNU, AC_FUNC_REALLOC, AC_TYPE_MBSTATE_T.
1276 - AC_FUNC_GETLOADAVG
1277 looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
1280 Now defines HAVE_MALLOC to 0 if `malloc' does not work, and asks
1281 for an AC_LIBOBJ replacement.
1285 - Spurious complaints from `m4_bmatch' about invalid regular
1286 expressions are suppressed.
1288 - Empty top_builddirs are properly handled.
1290 - AC_CHECK_MEMBER works correctly when the member is an aggregate.
1293 Now colon in the optional path arguments are properly handled.
1295 ** Improved portability
1297 - Both Autoconf the package, and the scripts it produces, should run
1298 more reliably with Zsh. Bear in mind it is the default Bourne shell
1301 - Autoconf and the scripts it produces no longer assume the existence of
1302 the obsolescent commands egrep and fgrep.
1306 - Limitations of Make
1310 The GNATS base moved to
1311 http://bugs.gnu.org/cgi-bin/gnatsweb.pl?database=autoconf
1312 (It is no longer available, though.)
1317 Now contains the list of output variables and files (AC_SUBST,
1320 * Major changes in Autoconf 2.53
1322 Released 2002-03-08 by Akim Demaille.
1326 Perl 5.005_03 or later is required: autom4te is written in Perl and is
1327 needed by autoconf. autoheader, autoreconf, ifnames, and autoscan are
1333 Argument requirements, output variables, defined macros.
1334 - M4sugar, M4sh, Autotest
1336 - Double quoting macros
1337 AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
1339 The Autoconf manual is now distributed under the terms of the GNU FDL.
1340 - Section `Hosts and Cross-Compilation'
1341 Explains the rationale for the 2.5x changes in the cross-compilation
1342 chain, and in the relationships between build, host, and target
1344 Emphasizes that `cross-compilation' == `--host is given'.
1345 If you are working on compilers etc., be sure to read this section.
1346 - Section `AC_LIBOBJ vs. LIBOBJS'
1347 Explains why assigning LIBOBJS directly is now an error.
1348 Details how to update the code.
1353 Now used instead of hard coded line numbers.
1354 This eases the comparison of `configure's, and diminishes the
1355 pressure over control version archives.
1356 Automatic replacement for shells that don't support this feature.
1357 - New output variables
1358 @builddir@, @top_builddir@, @abs_srcdir@, @abs_top_srcdir@, @abs_builddir@,
1363 Autoconf and Autotest modes are provided.
1368 New, used by the Autoconf suite to cache and speed up most processing.
1370 Supported by autom4te, autoconf and autoheader.
1372 Replaces --autoconf-dir and --localdir in autoconf, autoheader,
1373 autoupdate, and autoreconf.
1375 No longer passes --cygnus, --foreign, --gnits, --gnu, --include-deps:
1376 automake options are to be given via AUTOMAKE_OPTIONS.
1378 Runs gettextize and libtoolize when appropriate.
1380 --m4dir is no longer supported.
1382 Now runs only in the specified directories, defaulting to `.',
1383 but understands AC_CONFIG_SUBDIRS for dependent directories.
1384 Before, it used to run on all the `configure.ac' found in the
1386 Independent packages are properly updated.
1390 - The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
1392 Under the user pressure, $? is finally available. Probably a mistake.
1393 - AC_F77_LIBRARY_LDFLAGS now supports the HP/UX f90 compiler.
1394 - Precious variables accumulation
1395 config.status could stack several copies of the precious variables
1397 - AC_PATH_PROG and family.
1398 Works properly when given a literal path.
1400 Somewhere since 2.13, the result had been reversed.
1404 - AC_C_BIGENDIAN supports the cross-compiling case.
1405 - AC_C_BIGENDIAN accepts ACTION-IF-TRUE, ACTION-IF-FALSE, and
1406 ACTION-IF-UNKNOWN arguments. All are optional, and the default
1407 for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
1409 - AC_C_LONG_DOUBLE now succeeds only if `long double' has more range or
1410 precision than `double'.
1415 It now defines the preprocessor symbols PACKAGE_NAME,
1416 PACKAGE_TARNAME, PACKAGE_VERSION, PACKAGE_STRING, and
1420 Admits a fourth optional parameter: the tar name.
1422 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS.
1423 Provide the user with srcdir, ac_srcdir, ac_top_srcdir, ac_builddir,
1424 ac_top_builddir, ac_abs_srcdir, ac_abs_top_srcdir, ac_abs_builddir,
1425 ac_abs_top_builddir.
1427 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS and AC_OUTPUT.
1428 Are much less expensive when using long lists of files.
1431 Works with shell variables, and non alphanumeric names.
1435 - AC_FUNC_STRERROR_R now sets STRERROR_R_CHAR_P, not HAVE_WORKING_STRERROR_R,
1436 because POSIX 1003.1-200x draft 7 says strerror_r returns int, not char *.
1438 - AC_FUNC_STRTOD substitutes POW_LIB.
1443 * Major changes in Autoconf 2.52
1445 Released 2001-07-18 by Akim Demaille.
1450 This feature was present in autoconf 2.50 but was not documented.
1451 For example, `@<:@' is translated to `[' just before output. This
1452 is useful when writing strings that contain unbalanced quotes, or
1453 other hard-to-quote constructs.
1454 - m4_pattern_forbid, m4_pattern_allow
1455 - Tips for upgrading from 2.13.
1456 - Using autoscan to maintain a configure.ac.
1459 - Now include stdint.h.
1460 - sys/types.h and sys/stat.h are guarded.
1461 - strings.h is included if available, and not conflicting with string.h.
1464 - The test suite is more robust and presents less false failures.
1465 - Invocation of GNU M4 now robust to POSIXLY_CORRECT.
1466 - configure accepts --prefix='' again.
1467 - AC_CHECK_LIB works properly when its first argument is not a
1469 - HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
1470 - build_, host_, and target_alias are AC_SUBST as in 2.13.
1471 - AC_ARG_VAR properly propagates precious variables inherited from the
1472 environment to ./config.status.
1473 - Using --program-suffix/--program-prefix is portable.
1474 - Failures to detect the default compiler's output extension are less
1476 - `config.status foo' works properly when `foo' depends on variables
1477 set in an AC_CONFIG_THING INIT-CMD.
1478 - autoheader is more robust to broken input.
1479 - Fixed Fortran name-mangling and link tests on a number of systems,
1480 e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
1483 - AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
1484 specify pre-includes. In this case, the headers are compiled with
1485 cc, not merely preprocessed by cpp. Therefore it is the _usability_
1486 of a header which is checked for, not just its availability.
1487 - AC_ARG_VAR refuses to run configure when precious variables have
1489 - Versions of compilers are dumped in the logs.
1490 - AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
1493 - AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
1494 - AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
1495 - AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
1496 AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
1497 Be sure to read `Upgrading from Version 2.13' to understand why
1498 running `autoupdate' is needed.
1499 - AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
1500 a main-like routine is required/possible when linking C/C++ with
1501 Fortran. Users of e.g. AC_F77_WRAPPERS should be aware of these.
1502 - AC_FUNC_GETPGRG behaves better when cross-compiling.
1504 * Major changes in Autoconf 2.51
1505 There was no release of Autoconf 2.51 since some packagers had used
1506 this version number without permission to ship intermediary versions
1507 of 2.50. The version was skipped to avoid confusion.
1509 * Major changes in Autoconf 2.50
1511 Released 2001-05-21 by Akim Demaille.
1513 ** Lots of bug fixes
1514 There have been far too many to enumerate them here. Check out
1515 ChangeLog if you really want to know more.
1517 ** Improved documentation
1518 In particular, portability issues are better covered.
1521 All the standard GNU Makefile targets are supported. The layout has
1522 changed: m4/ holds the M4 extensions Autoconf needs for its
1523 configuration, doc/ contains the documentation, and tests/ contains
1526 ** Man pages are provided
1527 For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
1528 config.guess, config.sub.
1532 Provides a safe and powerful means to trace the macro uses. This
1533 provide the parsing layer for tools which need to `study'
1537 Specify what category of warnings should be enabled.
1539 - When recursing into subdirectories, try for configure.gnu before
1540 configure to adapt for packages not using autoconf on case-insensitive
1544 More errors are now caught (circular AC_REQUIRE dependencies,
1545 AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
1546 etc.). In addition, their location and call stack are given.
1549 autoupdate is much more powerful, and is able to provide the glue code
1550 which might be needed to move from an old macro to its newer
1553 You are strongly encouraged to use it to modernize both your
1554 `configure.in' and your .m4 extension files.
1557 The internal machinery of autoheader has completely changed. As a
1558 result, using `acconfig.h' should be considered to be obsoleted, and
1559 you are encouraged to get rid of it using the AH macros.
1564 ** Fortran 77 compilers
1565 Globally, the support for Fortran 77 is considerably improved.
1567 Support for automatically determining a Fortran 77 compiler's
1568 name-mangling scheme. New CPP macros F77_FUNC and F77_FUNC_ are
1569 provided to wrap C/C++ identifiers, thus making it easier and more
1570 transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
1571 call C/C++ routines. See the Texinfo documentation for details.
1574 The test suite no longer uses DejaGNU. It should be easy to submit
1575 test cases in this new framework.
1578 - --help, --help=long, -hl
1579 no longer dumps useless items.
1581 lists only specific options.
1582 - --help=recursive, -hr
1583 displays the help of all the embedded packages.
1584 - Remembers environment variables when reconfiguring.
1585 The previous scheme to set envvar before running configure was
1587 what prevented configure from remembering the environment in which
1588 it was run, therefore --recheck was run in an inconsistent
1589 environment. Now, one should run
1591 and then --recheck will work properly. Variables declared with
1592 AC_ARG_VAR are also preserved.
1594 $build defaults to `config.guess`, $host to $build, and then $target
1596 Cross-compilation is a global status of the package, it no longer
1597 depends upon the current language.
1598 Cross compilation is enabled iff the user specified `--host'.
1599 `configure' now fails if it can't run the executables it compiles,
1600 unless cross-compilation is enabled.
1602 The cache file is disabled by default. The new options
1603 `--config-cache', `-C' set the cache to `config.cache'.
1607 Much faster on most architectures.
1608 - concurrent executions
1609 It is safe to use `make -j' with config.status.
1610 - human interface improved
1611 It is possible to invoke
1612 ./config.status foobar
1613 instead of the former form (still valid)
1614 CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
1615 CONFIG_FILES=foobar:foo.in:bar.in \
1617 The same holds for configuration headers and links.
1618 You can instantiate unknown files and headers:
1619 ./config.status --header foo.h:foo.h.in --file bar:baz
1620 - has a useful --help
1621 - accepts special file name "-" for stdin/stdout
1626 Specify additional copyright information.
1629 Now expects the identity of the package as argument.
1633 Most macros, if not all, now strictly follow the `one quotation
1634 level' rule. This results in a more predictable expansion.
1637 A sly bug in the AC_REQUIRE machinery, which could produce incorrect
1638 configure scripts, was fixed by Axel Thimm.
1642 Document and ask for the registration of an envvar.
1645 Specifies the file which `configure' should look for when trying to
1646 find the source tree (used to be handled by AC_INIT).
1648 - AC_CONFIG_COMMANDS
1649 To add new actions to config.status. Should be used instead of
1653 Replaces AC_LINK_FILES.
1655 - AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
1656 AC_CONFIG_LINKS, and AC_CONFIG_FILES
1657 They now obey sh: you should no longer use shell variables as
1658 argument. Instead of
1660 test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
1661 AC_CONFIG_SUBDIRS($my_subdirs)
1665 if test "$package_foo_enabled" = yes; then
1666 AC_CONFIG_SUBDIRS(foo)
1670 To format an Autoconf macro's help string so that it looks pretty
1671 when the user executes `configure --help'.
1674 ** Generic Test Macros
1676 The interface of the AC_CHECK families of macros (decl, header,
1677 type, member, func) is now uniform. They support the same set of
1680 - AC_CHECK_DECL, AC_CHECK_DECLS
1681 To check whether a symbol is declared.
1683 - AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
1684 No longer need a cross-compilation default.
1687 The test it performs is much more robust than previously, and makes
1688 it possible to test builtin types in addition to typedefs.
1689 It is now schizophrenic:
1690 - AC_CHECK_TYPE(TYPE, REPLACEMENT)
1691 remains for backward compatibility, but its use is discouraged.
1692 - AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
1693 behaves exactly like the other AC_CHECK macros.
1696 Checks whether given types are supported by the system.
1698 - AC_CHECK_MEMBER, AC_CHECK_MEMBERS
1699 Check for given members in aggregates (e.g., pw_gecos in struct
1703 Checks if the compiler supports ISO C, included when needs special
1707 Checking whether the preprocessor indicates missing includes by the
1708 error code. stderr is checked by AC_TRY_CPP only as a fallback.
1711 Takes a language as argument and replaces AC_LANG_C,
1712 AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
1714 - AC_LANG_PUSH, AC_LANG_POP
1715 Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
1718 - AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
1719 AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
1720 AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
1724 Sets GETGROUPS_LIBS.
1726 - AC_FUNC_GETLOADAVG
1727 Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
1730 Now integrates `AC_DECL_YYTEXT' which is obsoleted.
1733 Arrange for large-file support.
1735 - AC_EXEEXT, AC_OBJEXT
1736 You are no longer expected to use them: their computation is
1737 performed by default.
1739 ** C++ compatibility
1740 Every macro has been revisited in order to support at best CC=c++.
1742 Major changes in Autoconf 2.14:
1743 There was no release of GNU Autoconf 2.14.
1745 Major changes in Autoconf 2.13:
1747 Released 1999-05-01 by Ben Elliston.
1749 * Support for building on 32-bit Windows systems where the only available C or
1750 C++ compiler is the Microsoft Visual C++ command line compiler
1751 (`cl'). Additional support for building on 32-bit Windows systems which are
1752 using the Cygwin or Mingw32 environments.
1753 * Support for alternative object file and executable file extensions.
1754 On 32-bit Windows, for example, these are .obj and .exe. These are discovered
1755 using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
1756 @EXEEXT@ in the output, respectively.
1757 * New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
1758 AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
1759 AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
1760 * AC_DEFINE now has an optional third argument for a description to be
1761 placed in the config header input file (e.g. config.h.in).
1762 * The C++ code fragment compiled for the C++ compiler test had to be
1763 improved to include an explicit return type for main(). This was
1764 causing failures on systems using recent versions of the EGCS C++
1766 * Fixed an important bug in AC_CHECK_TYPE that would cause a configure
1767 script to report that `sometype_t' was present when only `type_t'
1769 * Merge of the FSF version of config.guess and config.sub to modernize
1770 these scripts. Add support for a few new hosts in config.guess.
1771 Incorporate latest versions of install-sh, mkinstalldirs and
1772 texinfo.tex from the FSF.
1773 * autoreconf is capable of running automake if necessary (and
1775 * Support for Fortran 77. See the Texinfo documentation for details.
1776 * Bug fixes and workarounds for quirky bugs in vendor utilities.
1778 Major changes in Autoconf 2.12:
1780 Released 1996-11-26 by David J. MacKenzie
1782 * AC_OUTPUT and AC_CONFIG_HEADER can create output files by
1783 concatenating multiple input files separated by colons, like so:
1784 AC_CONFIG_HEADER(config.h:conf.pre:config.h.in:conf.post)
1785 AC_OUTPUT(Makefile:Makefile.in:Makefile.rules)
1786 The arguments may be shell variables, to compute the lists on the fly.
1787 * AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
1788 * New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
1791 Major changes in Autoconf 2.11:
1793 Released November 18th, 1996, by David J. MacKenzie
1795 * AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
1796 They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
1797 * AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
1798 * AC_CONFIG_HEADER expands shell variables in its argument.
1799 * New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
1800 * The "checking..." messages and the source code for test programs that
1801 fail are saved in config.log.
1802 * Another workaround has been added for seds with small command length limits.
1803 * config.sub and config.guess recognize more system types.
1806 Major changes in Autoconf 2.10:
1808 Released May 7th, 1996, by Roland McGrath
1811 * The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
1812 changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
1814 Major changes in Autoconf 2.9:
1816 Released March 16th, 1996, by Roland McGrath
1820 Major changes in Autoconf 2.8:
1822 Released March 8th, 1996, by Roland McGrath
1826 Major changes in Autoconf 2.7:
1828 Released November 22nd, 1995, by David J. MacKenzie
1832 Major changes in Autoconf 2.6:
1834 Released November 20th, 1995, by David J. MacKenzie
1838 Major changes in Autoconf 2.5:
1840 Released November 17th, 1995, by Roland McGrath
1842 * New configure options --bindir, --libdir, --datadir, etc., with
1843 corresponding output variables.
1844 * New macro: AC_CACHE_CHECK, to make using the cache easier.
1845 * config.log contains the command being run as well as any output from it.
1846 * AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
1847 * AC_PROG_INSTALL doesn't cache a name for install-sh, for sharing caches.
1848 * AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
1849 AC_CHECK_TOOL can search a path other than $PATH.
1850 * AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
1852 Major changes in Autoconf 2.4:
1854 Released June 14th, 1995, by David J. MacKenzie
1856 * Fix a few bugs found by Emacs testers.
1858 Major changes in Autoconf 2.3:
1860 Released March 27th, 1995, by David J. MacKenzie
1862 * Fix the cleanup trap in several ways.
1863 * Handle C compilers that are picky about option placement.
1864 * ifnames gets the version number from the right directory.
1866 Major changes in Autoconf 2.2:
1868 Released March 8th, 1995, by David J. MacKenzie
1870 * The ifnames utility is much faster but requires a "new awk" interpreter.
1871 * AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
1872 library before existing libs, not after, in case it uses them.
1873 * New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
1874 * Lots of bug fixes.
1875 * Many additions to the TODO file :-)
1877 Major changes in Autoconf 2.1:
1879 Released November 4th, 1994, by David J. MacKenzie
1882 * More explanations in the manual.
1883 * Fix a spurious failure in the testsuite.
1884 * Clarify some warning messages.
1885 * autoreconf by default only rebuilds configure and config.h.in files
1886 that are older than any of their particular input files; there is a
1887 --force option to use after installing a new version of Autoconf.
1889 Thanks to everybody who's submitted changes and additions to Autoconf!
1890 I've incorporated many of them, and am still considering others for
1891 future releases -- but I didn't want to postpone this release indefinitely.
1893 Caution: don't indiscriminately rebuild configure scripts with
1894 Autoconf version 2. Some configure.in files need minor adjustments to
1895 work with it; the documentation has a chapter on upgrading. A few
1896 configure.in files, including those for GNU Emacs and the GNU C
1897 Library, need major changes because they relied on undocumented
1898 internals of version 1. Future releases of those packages will have
1899 updated configure.in files.
1901 It's best to use GNU M4 1.3 (or later) with Autoconf version 2.
1902 Autoconf now makes heavy use of M4 diversions, which were implemented
1903 inefficiently in GNU M4 releases before 1.3.
1905 Major changes in Autoconf 2.0:
1907 Released October 26th, 1994, by David J. MacKenzie
1909 ** New copyright terms:
1910 * There are no restrictions on distribution or use of configure scripts.
1913 * Autoconf manual is reorganized to make information easier to find
1914 and has several new indexes.
1915 * INSTALL is reorganized and clearer and is now made from Texinfo source.
1918 * autoscan to generate a preliminary configure.in for a package by
1919 scanning its source code for commonly used nonportable functions,
1920 programs, and header files.
1921 * ifnames to list the symbols used in #if and #ifdef directives in a
1923 * autoupdate to update a configure.in to use the version 2 macro names.
1924 * autoreconf to recursively remake configure and configuration header
1925 files in a source tree.
1927 ** Changed utilities:
1928 * autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
1929 * autoconf and autoheader can look for package-local definition files
1930 in an alternate directory.
1933 * AC_CACHE_VAL to share results of tests between configure runs.
1934 * AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
1935 that macros invoked with AC_REQUIRE don't interrupt other macros.
1936 * AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
1937 support deciding unguessable features based on the host and target types.
1938 * AC_CONFIG_SUBDIRS to recursively configure a source tree.
1939 * AC_ARG_PROGRAM to use the options --program-prefix,
1940 --program-suffix, and --program-transform-name to change the names
1941 of programs being installed.
1942 * AC_PREFIX_DEFAULT to change the default installation prefix.
1943 * AC_TRY_COMPILE to compile a test program without linking it.
1944 * AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
1945 * AC_CHECK_LIB to check for a particular function and library.
1946 * AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
1947 whether or not the test succeeds. They obsolete AC_CHECKING and AC_VERBOSE.
1948 * AC_SUBST_FILE to insert one file into another.
1949 * AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
1950 * AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
1951 * AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
1952 * AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
1955 * Many macros renamed systematically, but old names are accepted for
1956 backward compatibility.
1957 * AC_OUTPUT adds the "automatically generated" comment to
1958 non-Makefiles where it finds @configure_input@ in an input file, to
1959 support files with various comment syntaxes.
1960 * AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
1961 files when they are not enclosed in @ signs.
1962 * AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
1963 override the file name "config.status".
1964 * AC_OUTPUT takes an optional argument for passing variables from
1965 configure to config.status.
1966 * AC_OUTPUT and AC_CONFIG_HEADER allow you to override the input-file names.
1967 * AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
1968 CPPFLAGS, and LDFLAGS from the environment.
1969 * AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
1970 * AC_PROG_INSTALL looks for install-sh or install.sh in the directory
1971 specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
1972 srcdir/../.. by default.
1973 * AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
1974 * AC_DEFINE no longer prints anything, because of the new result reporting
1975 mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
1976 * AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
1977 * AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
1978 --enable- and --with- options.
1979 * AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
1980 execute on success or failure.
1981 * Checking for C functions in C++ works.
1984 * AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
1985 better maintained with them.
1986 * AC_ARG_ARRAY removed because no one was likely using it.
1987 * AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
1988 take arguments, for consistency with all of the other specific checks.
1991 * Comes with config.sub and config.guess, and uses them optionally.
1992 * Uses config.cache to cache test results. An alternate cache file
1993 can be selected with the --cache-file=FILE option.
1994 * Uses optional shell scripts $prefix/share/config.site and
1995 $prefix/etc/config.site to perform site or system specific initializations.
1996 * configure saves compiler output to ./config.log for debugging.
1997 * New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
1998 * acsite.m4 is the new name for the system-wide aclocal.m4.
1999 * Has a DejaGnu test suite.
2001 Major changes in Autoconf 1.11:
2003 * AC_PROG_INSTALL calls install.sh with the -c option.
2004 * AC_SET_MAKE cleans up after itself.
2005 * AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
2006 * AC_OUTPUT prevents shells from looking in PATH for config.status.
2008 Plus a few other bug fixes.
2010 Major changes in Autoconf 1.10:
2012 * autoheader uses config.h.bot if present, analogous to config.h.top.
2013 * AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
2015 * AC_PROG_CXX looks for cxx as a C++ compiler.
2017 Plus several bugs fixed.
2019 Major changes in Autoconf 1.9:
2021 * AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
2022 * AC_SIZEOF_TYPE generates the cpp symbol name automatically,
2023 and autoheader generates entries for those names automatically.
2024 * AC_FIND_X gets the result from xmkmf correctly.
2025 * AC_FIND_X assumes no X if --without-x was given.
2026 * AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
2027 * AC_PROG_INSTALL finds OSF/1 installbsd.
2029 Major changes in Autoconf 1.8:
2032 * New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
2033 AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
2034 for checking both C++ and C features in one configure script.
2035 * New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
2036 * New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
2037 AC_SET_MAKE, AC_ENABLE.
2040 * AC_FIND_X looks for X in more places.
2041 * AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
2042 install.sh is distributed with Autoconf.
2043 * AC_DECLARE_YYTEXT has been removed because it can't work, pending
2044 a rewrite of quoting in AC_DEFINE.
2045 * AC_OUTPUT adds its comments in C format when substituting in C files.
2046 * AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
2048 ** New or changed command line options:
2049 * configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
2050 * configure accepts --without-PACKAGE, which sets withval=no.
2051 * configure accepts --x-includes=DIR and --x-libraries=DIR.
2052 * Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
2053 * configure accepts --help, --version, --silent/--quiet, --no-create options.
2054 * configure accepts and ignores most other Cygnus configure options, and
2055 warns about unknown options.
2056 * config.status accepts --help, --version options.
2058 ** File names and other changes:
2059 * Relative srcdir values are not made absolute.
2060 * The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
2061 * Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
2062 * autoheader optionally copies config.h.top to the beginning of config.h.in.
2063 * The example Makefile dependencies for configure et al. work better.
2064 * Namespace cleanup: all shell variables used internally by Autoconf
2065 have names beginning with `ac_'.
2067 More big improvements are in process for future releases, but have not
2068 yet been (variously) finished, integrated, tested, or documented enough
2071 Major changes in Autoconf 1.7:
2073 * New macro AC_OBSOLETE.
2074 * Bugs in Makefile.in fixed.
2075 * AC_LONG_FILE_NAMES improved.
2077 Major changes in Autoconf 1.6:
2079 * New macro AC_LONG_64_BITS.
2080 * Multiple .h files can be created.
2081 * AC_FIND_X looks for X files directly if it doesn't find xmkmf.
2082 * AC_ALLOCA defines C_ALLOCA if using alloca.c.
2083 * --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
2084 * Unused --no-create option to configure removed.
2085 * autoheader doesn't change the timestamp of its output file if
2086 the file didn't change.
2087 * All macros that look for libraries now use AC_HAVE_LIBRARY.
2088 * config.status checks three optional environment variables to
2089 modify its behavior.
2090 * The usual bug fixes.
2092 Major changes in Autoconf 1.5:
2094 * New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
2095 * autoconf and autoheader scripts have GNU standards conforming
2096 --version and --help options (they print their message and exit).
2099 Major changes in Autoconf 1.4:
2101 * New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
2102 AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
2103 * autoconf and autoheader use the M4 environment variable to determine the
2104 name of the M4 program to use.
2105 * The --macrodir option to autoconf and autoheader specifies the directory
2106 in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
2107 * autoconf and autoheader can take `-' as their file names, which means to
2108 read stdin as input.
2109 * Resulting configure scripts can take a --verbose option which causes them
2110 to print the results of their tests.
2111 * AC_DEFINE quotes its second argument in such a way that spaces, magic
2112 shell characters, etc. will be preserved during various stages of
2113 expansion done by the shell. If you don't want this, use
2114 AC_DEFINE_UNQUOTED instead.
2115 * Much textual processing done with external calls to tr and sed have been
2116 internalized with builtin M4 `patsubst' and `translit' calls.
2117 * AC_OUTPUT doesn't hardwire the file names it outputs. Instead, you can
2118 set the shell variables `gen_files' and `gen_config' to the list of
2119 file names to output.
2120 * AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
2121 "lex.yy" or "lexyy", depending on the system.
2122 * AC_PROGRAMS_CHECK takes an optional third arg. If given, it is used as
2124 * If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
2125 * AC_CONST works much more reliably on more systems.
2128 Major changes in Autoconf 1.3:
2130 configure no longer requires awk for packages that use a config.h.
2131 Support handling --with-PACKAGE options.
2132 New `autoheader' script to create `config.h.in' from `configure.in'.
2133 Ignore troublesome -lucb and -lPW when searching for alloca.
2134 Rename --exec_prefix to --exec-prefix for GNU standards conformance.
2135 Improve detection of STDC library.
2136 Add AC_HAVE_LIBRARY to check for non-default libraries.
2137 Function checking should work with future GNU libc releases.
2139 Major changes in Autoconf 1.2:
2141 The --srcdir option is now usually unnecessary.
2142 Add a file containing sample comments describing CPP macros.
2143 A comment in config.status tells which host it was configured on.
2144 Substituted variable values can now contain commas.
2145 Fix bugs in various feature checks.
2147 Major changes in Autoconf 1.1:
2149 Added AC_STRCOLL macro.
2150 Made AC_GETLOADAVG check for more things.
2151 AC_OUTPUT argument is now optional.
2156 Copyright (C) 1993-1996, 1998-2013 Free Software Foundation, Inc.
2158 Copying and distribution of this file, with or without modification,
2159 are permitted in any medium without royalty provided the copyright
2160 notice and this notice are preserved. This file is offered as-is,
2161 without warranty of any kind.