1 GNU Autoconf NEWS - User visible changes.
3 * Major changes in Autoconf 2.64 (2009-??-??) [stable]
4 Released by Eric Blake, based on git versions 2.63b.*.
6 ** AS_IF, AS_CASE, and AS_FOR have been taught to avoid syntax errors
7 even when given arguments that expand to just whitespace.
9 ** Ensure AT_CHECK can support commands that include a # given with
10 proper m4 quoting. For shell comments, this is a new feature; for
11 non-shell comments, this fixes a regression introduced in 2.63b.
13 ** The following documented m4sugar macros are new:
14 m4_default_nblank m4_default_nblank_quoted m4_ifblank m4_ifnblank
16 * Major changes in Autoconf 2.63b (2009-03-31) [beta]
17 Released by Eric Blake, based on git versions 2.63.*.
19 ** The manual is now shipped under the terms of the GNU FDL 1.3.
21 ** AC_REQUIRE now detects the case of an outer macro which first expands
22 then later indirectly requires the same inner macro. Previously,
23 this case led to silent out-of-order expansion (bug present since
24 2.50); it now issues a syntax warning, and duplicates the expansion
25 of the inner macro to guarantee dependencies have been met. See
26 the manual for advice on how to refactor macros in order to avoid
27 the bug in earlier autoconf versions and avoid increased script
28 size in the current version.
30 ** AC_DEFUN_ONCE has improved semantics. Previously, a macro declared
31 with AC_DEFUN_ONCE warned on a second invocation; and out-of-order
32 expansion was still possible. Now, dependencies are guaranteed,
33 and subsequent invocations are a silent no-op. This makes
34 AC_DEFUN_ONCE an ideal macro for silencing AC_REQUIRE warnings.
36 ** The following macros are now defined with AC_DEFUN_ONCE. This means
37 a subtle change in semantics; previously, an AC_DEFUN macro could
38 expand one of these macros multiple times or surround the macro
39 inside shell conditional text to bypass the effects of these
40 macros, but now the macro will expand exactly once, and prior to
41 the start of any enclosing AC_DEFUN macro:
42 AC_CANONICAL_BUILD AC_CANONICAL_HOST AC_CANONICAL_TARGET
43 AC_HEADER_ASSERT AC_PROG_INSTALL AC_PROG_MKDIR_P
44 AC_USE_SYSTEM_EXTENSIONS
46 ** AC_LANG_ERLANG works once again (regression introduced in 2.61a).
48 ** AC_HEADER_ASSERT is fixed so that './configure --enable-assert' no
49 longer mistakenly disables assertions.
51 ** AC_INIT now takes an optional fifth parameter that can be used to
52 set AC_PACKAGE_URL, a URL for the package's home page; the URL is
53 used in `configure --help' and is also available via AC_DEFINE.
55 ** Autotest testsuites accept an option --jobs[=N] for parallel testing.
56 This feature is still in testing, and may not work on every
57 platform, help in improving it would be appreciated.
59 ** Autotest testsuites do not attempt to write startup error messages
60 to the log file before that is opened (regression introduced in 2.63).
62 ** Configure scripts now use shell functions. This feature leads to
63 smaller configure files and faster execution.
65 ** Present But Cannot Be Compiled: Autoconf will now proceed with
66 the compiler's result if a header is present but cannot be compiled.
67 The warning is still printed, and you should really fix it by
68 providing a fourth parameter to AC_CHECK_HEADER/AC_CHECK_HEADERS.
70 ** Autoreconf added aclocal to the set of programs affected by the
71 `autoreconf -I dir' option.
73 ** The following documented m4sugar macros are new:
74 m4_chomp m4_chomp_all m4_cleardivert m4_curry m4_default_quoted
75 m4_esyscmd_s m4_map_args m4_map_args_pair m4_map_args_sep
76 m4_map_args_w m4_set_map m4_set_map_sep m4_stack_foreach
77 m4_stack_foreach_lifo m4_stack_foreach_sep
78 m4_stack_foreach_sep_lifo
80 ** The following m4sugar macros are documented now, but in some cases
81 with slightly different semantics than what the previous
82 undocumented version had:
83 m4_copy m4_dumpdefs m4_rename m4_version_prereq
85 ** The m4sugar macro m4_expand has been taught to handle unterminated
86 comments and shell case statements. As a result, it is used
87 internally in more places, such as AC_DEFINE and AT_CHECK. Most
88 uses of AC_DEFINE and AT_CHECK should not behave any differently;
89 however, it may be necessary to add double-quoting around
90 unbalanced `(' where single-quoting used to be sufficient.
92 ** The following documented m4sh macros are new:
93 AS_INIT_GENERATED AS_LINENO_PREPARE AS_ME_PREPARE AS_SET_STATUS
94 AS_VAR_APPEND AS_VAR_ARITH AS_VAR_COPY
96 ** The following m4sh macros are documented now, but in some cases
97 with slightly different semantics than what the previous
98 undocumented version had:
99 AS_ECHO AS_ECHO_N AS_ESCAPE AS_EXIT AS_LITERAL_IF AS_UNSET
100 AS_VAR_IF AS_VAR_POPDEF AS_VAR_PUSHDEF AS_VAR_SET AS_VAR_SET_IF
101 AS_VAR_TEST_SET AS_VERSION_COMPARE
103 ** The m4sh macros AS_IF and AS_CASE can now be used in shell lists.
104 The responsibility for supplying a trailing newline now belongs to
105 the call site, but since most users did not add dnl, this generally
106 results in fewer empty lines in configure.
109 * Major changes in Autoconf 2.63 (2008-09-09) [stable]
110 Released by Eric Blake, based on git versions 2.62.*.
112 ** AC_C_BIGENDIAN does not mistakenly report "universal" for some
113 bigendian hosts, a regression introduced with universal binary
116 ** AC_PATH_X now includes /lib64 and /usr/lib64 in its list of default
119 ** AC_USE_SYSTEM_EXTENSIONS no longer conflicts with an external
120 AC_DEFINE([__EXTENSIONS__]). This fixes a regression introduced in
121 2.62 when using macros such as AC_AIX that were made obsolete in
122 favor of the more portable AC_USE_SYSTEM_EXTENSIONS.
124 ** AC_CHECK_TARGET_TOOLS is usable in the non-cross-compile case.
126 ** Newly obsolete macros
127 The following macro has been marked obsolete, since current porting
128 targets can safely assume C89 semantics that signal handlers return
129 void. We have no current plans to remove the macro.
133 ** The macros m4_map and m4_map_sep now ignore any list elements
134 consisting of just empty quotes, and m4_map_sep now expands its
135 separator. This fixes a regression in 2.62 when these macros were
136 first documented, for the sake of clients expecting the semantics
137 that these macros had prior to that time. The new macros m4_mapall
138 and m4_mapall_sep, along with extra quoting of the separator, can
139 be used to get the semantics that m4_map_sep had in 2.62.
141 ** Clients of m4_expand, such as AS_HELP_STRING and AT_SETUP, can now
142 handle properly quoted but otherwise unbalanced parentheses (for
143 some macros, this fixes a regression in 2.62).
145 ** Two new quadrigraphs have been introduced: @{:@ for (, and @:}@ for ),
146 allowing the output of unbalanced parentheses in more contexts.
148 ** The following m4sugar macros are new:
149 m4_cleardivert m4_joinall m4_mapall m4_mapall_sep m4_reverse
150 m4_set_add m4_set_add_all m4_set_contains m4_set_contents
151 m4_set_delete m4_set_difference m4_set_dump m4_set_empty
152 m4_set_foreach m4_set_intersection m4_set_list m4_set_listc
153 m4_set_remove m4_set_size m4_set_union
155 ** The following m4sugar macros now accept multiple arguments, as is the
156 case with underlying m4:
157 m4_defn m4_popdef m4_undefine
159 ** The following m4sugar macros now guarantee linear scaling; they
160 previously had linear scaling with m4 1.6 but quadratic scaling
161 when using m4 1.4.x. All macros built on top of these also gain
162 the scaling improvements.
163 m4_bmatch m4_bpatsubsts m4_case m4_cond m4_do m4_dquote_elt
164 m4_foreach m4_join m4_list_cmp m4_map m4_map_sep m4_max
167 ** AT_KEYWORDS once again performs expansion on its argument, such that
168 AT_KEYWORDS([m4_if([$1], [], [default])]) no longer complains about
169 the possibly unexpanded m4_if [regression introduced in 2.62].
171 ** Config header templates `#undef UNDEFINED /* comment */' do not lead to
172 nested comments any more; regression introduced in 2.62.
175 * Major changes in Autoconf 2.62 (2008-04-05) [stable]
176 Released by Eric Blake, based on git versions 2.61a.*.
178 ** Many optimizations have been applied to make overall execution faster.
180 ** Autotest now makes use of shell functions.
182 ** config.status now uses awk instead of sed also for config headers.
184 - As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
185 values, i.e., backslash-newline combinations are handled correctly.
186 Further, for config headers, the total size of values is not limited by
187 the POSIX length limit of text lines any more, only each single line.
189 ** New config variable `top_build_prefix'.
191 ** New Autoconf macros:
192 AC_AUTOCONF_VERSION AC_OPENMP AC_PATH_PROGS_FEATURE_CHECK
194 ** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.
196 ** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
197 like '__restrict' if the variant spelling is available, as this is
198 more likely to work when mixing C and C++ code.
200 ** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
201 be a string of tokens such that "T y;" is a valid member declaration
204 ** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
205 is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.
207 ** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
208 they did not work for function types. In C++, they now work on any
209 type-id that can be the operand of sizeof; this is similar to C,
210 except it excludes anonymous struct and union types. Formerly,
211 some (but not all) C++ types involving anonymous struct and union
212 were accepted, though this was not documented.
214 ** AC_CONFIG_LINKS now prefers to link against files in the build tree
215 if found, and it works to link against a file of the same name in
216 the source tree, even if both trees coincide.
218 ** AC_INIT no longer alters $@; regression introduced in 2.60.
220 ** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.
222 ** AS_HELP_STRING no longer underquotes its first argument; it also handles
223 the case where the first argument contains single-quoted commas.
224 For example, "AS_HELP_STRING([-a, [--arg[=foo]]], [bar])" produces:
225 " -a, --arg[=foo] bar"
226 Additionally, the macro now takes two additional arguments,
227 indent-column and wrap-column; these should not normally be needed,
228 but can be used to fine-tune how the output text is wrapped.
230 ** AC_PROG_INSTALL now requires an install program that can install multiple
231 files into a target directory.
233 ** The command 'autoconf -' now correctly processes a file from stdin.
235 ** 'autoreconf -m' now honors $MAKE.
237 ** For all of the directory arguments for 'configure', such as '--prefix'
238 or '--bindir', trailing slashes are stripped. As an example, if
239 tab completion in the user's shell appends trailing slashes, the
240 command './configure --prefix=/usr/' will still result in an
241 expanded libdir value of /usr/lib, not /usr//lib.
243 ** `configure --help=recursive' now works in read-only trees and from
244 unconfigured build trees.
246 ** If precious variables differ only in whitespace, then the cache consistency
247 check warns instead of fails, and reuses the old value.
249 ** AT_BANNER is now documented.
251 ** AT_SETUP now handles macro expansions properly when calculating line
254 ** Autotest now determines $srcdir correctly.
256 ** Testsuites built by autotest now accept a -C/--directory=DIR option
257 to adjust the working directory prior to creating files.
259 ** Autoconf now requires GNU M4 1.4.5 or later. Earlier versions of M4 have
260 a bug in macro tracing that interferes with the interaction between
261 Autoconf and Automake. GNU M4 1.4.11 or later is recommended. The
262 configure search for a working M4 is improved.
264 ** For portability with the eventual M4 2.0, macros should no longer use
265 anything larger than $9 to refer to arguments.
267 ** Documentation for m4sugar is improved.
269 - The following macros were previously available as undocumented
270 interfaces; the macros are now documented as stable interfaces.
272 __oline__ m4_assert m4_bmatch m4_bpatsubsts m4_car m4_case
273 m4_cdr m4_default m4_divert_once m4_divert_pop m4_divert_push
274 m4_divert_text m4_do m4_errprintn m4_fatal m4_flatten
275 m4_ifndef m4_ifset m4_ifval m4_ifvaln m4_location
276 m4_n m4_shiftn m4_strip m4_warn
278 - The following macros were previously available as undocumented
279 interfaces, but had bug fixes or semantic changes as part of this
280 release. Packages that relied on the undocumented behavior
281 should be analyzed to make sure they will still work with the
282 new documented behavior.
284 m4_cmp m4_list_cmp m4_join m4_map m4_map_sep m4_sign
285 m4_text_box m4_text_wrap m4_version_compare
287 - The m4_wrap macro used to have unspecified order, but now
288 guarantees FIFO order. m4_wrap_lifo was added to guarantee LIFO
291 - Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
292 should consider using the new AC_AUTOCONF_VERSION instead.
294 - m4sugar macros that are not documented in the manual are still
295 deemed experimental, and should not be used outside of Autoconf.
297 ** The m4sugar macros m4_append and m4_append_uniq, first documented in
298 2.60, have been fixed to treat both the string and the separator
299 arguments consistently with regards to quoting. Prior to this fix,
300 m4_append_uniq could mistakenly duplicate entries if the expansion
301 of the separator resulted in a different string (for example, if it
302 contained quotes, a comma, or a macro name). However, it means
303 that programs previously using
304 m4_append([name], [string], [[, ]])
305 are now using a four-character separator instead of the intended
306 comma and space. If you need portability to earlier versions of
307 Autoconf, you can insert the following snippet after AC_INIT but
308 before any other macro expansions, to enforce the new semantics:
309 m4_pushdef([m4_append], [m4_define([$1],
310 m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
311 Additionally, m4_append_uniq now takes optional parameters that can
312 be used to take action depending on whether anything was appended,
313 and warns if a non-empty separator occurs within the string being
314 appended, since that can lead to duplicates.
316 ** The following m4sugar macros are new:
317 m4_append_uniq_w m4_apply m4_combine m4_cond m4_count
318 m4_dquote_elt m4_echo m4_expand m4_ignore m4_make_list m4_max
319 m4_min m4_newline m4_shift2 m4_shift3 m4_unquote m4_wrap_lifo
321 ** Warnings are now generated by default when an installer invokes
322 'configure' with an unknown --enable-* or --with-* option.
323 These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
324 macro, or by invoking 'configure' with --disable-option-checking.
326 ** Existing obsolete macros
327 The documentation for the following macros is adjusted to make it
328 more clear that they have previously been marked obsolete, as their
329 functionality can be accomplished by other macros. We have no
330 current plans to remove them from Autoconf.
332 AC_ENABLE AC_STRUCT_ST_BLKSIZE AC_STRUCT_ST_RDEV AC_WITH
334 ** Newly obsolete macros
335 The following macros have been marked obsolete, as they only
336 perform a subset of AC_USE_SYSTEM_EXTENSIONS. We have no current
337 plans to remove them.
339 AC_AIX AC_GNU_SOURCE AC_ISC_POSIX AC_MINIX
341 ** AC_C_LONG_DOUBLE is obsolescent.
342 The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
343 tests for problems that are so old that it is no longer of
344 practical importance on current systems. New programs need not use
345 AC_C_LONG_DOUBLE. We have no current plans to remove it.
347 ** AC_DIAGNOSE, AC_WARNING, and AC_FATAL are obsolescent.
348 The documentation now favors the use of M4sugar macros m4_warn and
349 m4_fatal, since the naming makes it more obvious that the
350 diagnostics are associated with M4 expansion (ie. when running
351 `autoconf'), and offers less confusion with the AC_MSG_ERROR,
352 AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
353 when running `configure'. We have no current plans to remove these
357 * Major changes in Autoconf 2.61a (2006-12-11)
359 ** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
360 on many platforms. This has been fixed.
362 ** AC_FUNC_SETVBUF_REVERSED is now obsolete. It is still defined for backward
363 compatibility but it does nothing. The macro was already
364 obsolescent, as the last systems to have the problem were those
365 based on SVR2, which became obsolete in 1987. The macro had bugs
366 on some modern systems and could no longer be maintained reliably
367 due to lack of ancient systems to test it on.
369 ** config.status now uses awk instead of sed for most substitutions, for speed.
371 - As a side effect multi-line values of substituted variables no
372 longer have a small limit in total size, though for portability
373 each line should not exceed the POSIX length limit for text lines.
375 - It is now documented that Makefile.in should not contain
376 overlapping variable occurrences, e.g., @VAR1@VAR2@.
377 Autoconf's behavior was always iffy in such cases, and the
378 awk implementation has changed the behavior.
380 ** Many uses of 'echo' have been rewritten so that Autoconf-generated
381 scripts have fewer problems with strings or file names containing
382 embedded special characters such as backslash or leading "-". This
383 was implemented by using `printf '%s\n' "$foo"' instead of `echo
384 "$foo"' when printf works. Due to the implementation technique
385 used, Autoconf-generated scripts now run considerably more slowly
386 on ancient implementations lacking printf. However, this should
387 not be a problem, since Autoconf-generated scripts in practice
388 invariably find a more-modern shell these days.
391 * Major changes in Autoconf 2.61 (2006-11-17)
393 ** New macros AC_C_FLEXIBLE_ARRAY_MEMBER, AC_C_VARARRAYS.
395 ** AC_ARG_ENABLE and AC_ARG_WITH now allow '.' in feature and package names.
398 * Major changes in Autoconf 2.60b (2006-10-22)
401 Autoconf-generated shell scripts no longer export BIN_SH, due to
402 configuration hassles with this. Installers who need BIN_SH in
403 their environment should set it before invoking 'configure' and
404 'make'. As far as we know, this affects only Unixware installations.
406 ** Obsolescent macros
407 The documentation now says that the following macros are obsolescent,
408 as they are superseded by Gnulib:
410 AC_FUNC_FNMATCH AC_FUNC_FNMATCH_GNU AC_FUNC_GETLOADVG AC_REPLACE_FNMATCH
412 New programs should use the Gnulib counterparts of these macros.
413 We have no current plans to remove them from Autoconf.
415 ** AC_COMPUTE_INT no longer caches or reports results.
417 ** AC_CHECK_DECL now also works with aggregate objects.
419 ** AC_USE_SYSTEM_EXTENSIONS now defines _TANDEM_SOURCE for NonStop platforms.
421 ** GNU M4 1.4.7 or later is now recommended.
424 New M4sugar macro, which is more secure than the POSIX M4 maketemp.
427 Now an alias for m4_mkstemp.
429 * Major changes in Autoconf 2.60a (2006-08-25)
431 ** GNU M4 1.4.6 or later is now recommended.
433 ** The check for C99 now tests for varargs macros, as documented.
434 It also tests that the preprocessor supports 64-bit integers.
436 ** Autoconf now uses constructs like "#ifdef HAVE_STDLIB_H" rather than
437 "#if HAVE_STDLIB_H", so that it now works with "gcc -Wundef -Werror".
439 ** The functionality of the undocumented _AC_COMPUTE_INT is now provided
440 by a public and documented macro, AC_COMPUTE_INT. The parameters to the
441 two macros are different, so autoupdate will not change the old private name
442 to the new one. _AC_COMPUTE_INT may be removed in a future release.
444 ** AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT now require
445 that long long types be at least 64 bits wide, as C99 and tradition
446 requires. Formerly, they accepted implementations of any width.
449 * Major changes in Autoconf 2.60
451 Released 2006-06-23, by Ralf Wildenhues.
453 ** Autoconf no longer depends on whether m4wrap is FIFO (as Posix requires)
454 or LIFO (as in GNU M4 1.4.x). GNU M4 2.0 is expected to conform to Posix
455 here, so m4wrap/m4_wrap users should no longer depend on LIFO behavior.
457 ** Provide a way to turn off warnings about the changed directory variables.
459 * Major changes in Autoconf 2.59d
461 Released 2006-06-05, by Ralf Wildenhues.
463 ** GNU make now recommended for VPATH builds
464 INSTALL now suggests VPATH builds (e.g., "sh ../srcdir/configure")
465 only if you use GNU make. In practice, other 'make' implementations
466 have too many subtle incompatibilities in their support for VPATH.
467 Many packages (including Autoconf itself) are portable to other
468 'make' implementations, but some packages are not, and recommending
469 GNU make keeps the installation instructions simpler.
471 ** Even more safety checks for the new Directory variables:
472 Warn about suspicious `${datarootdir}' found in config files output.
474 ** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
475 These never-documented macros and variables have been marked with
476 comments saying that they may be removed in a future release,
477 because their use can lead to unintended code being executed.
478 If you need functionality that only these macros or variables
479 currently supply, please write bug-autoconf@gnu.org.
481 ** AC_SUBST, AC_DEFINE
482 Literal arguments to these are passed to m4_pattern_allow now.
485 Passing 'ac_cv_prog_cc_stdc=no' to 'configure' now sets ac_cv_prog_cc_c99
486 and ac_cv_prog_cc_c89 to 'no' as well, for backward compatibility with
487 obsolete K&R tests in the Automake test suite.
496 Now more robust with special characters in file names, or when
497 multiple processes create the same directory at the same time.
499 ** Obsolescent macros
500 The documentation now says that the following macros are obsolescent:
501 they test for problems that are so old that they are no longer of
502 practical importance on current systems.
504 AC_C_BACKSLASH_A AC_FUNC_MEMCMP AC_HEADER_DIRENT
505 AC_C_CONST AC_FUNC_SELECT_ARGTYPES AC_HEADER_STAT
506 AC_C_PROTOTYPES AC_FUNC_SETPGRP AC_HEADER_STDC
507 AC_C_STRINGIZE AC_FUNC_SETVBUF_REVERSED AC_HEADER_SYS_WAIT
508 AC_C_VOLATILE AC_FUNC_STAT AC_HEADER_TIME
509 AC_FUNC_CLOSEDIR_VOID AC_FUNC_STRFTIME AC_ISC_POSIX
510 AC_FUNC_GETPGRP AC_FUNC_UTIME_NULL AC_PROG_GCC_TRADITIONAL
511 AC_FUNC_LSTAT AC_FUNC_VPRINTF AC_STRUCT_TM
513 New programs need not use these macros. We have no current plans to
517 For compatibility with future Libtool 2.0, autoreconf will invoke
518 libtoolize with the option `--ltdl' now, if LT_CONFIG_LTDL_DIR is
521 * Major changes in Autoconf 2.59c
523 Released 2006-04-12, by Ralf Wildenhues.
525 ** The configure command now redirects standard input from /dev/null,
526 to help avoid problems with subsidiary commands that might mistakenly
527 read standard input. AS_ORIGINAL_STDIN_FD points to the original
528 standard input before this redirection, if you really want configure to
529 read from standard input.
531 ** Directory variables adjusted to recent changes in the GNU Coding Standards.
532 The following directory variables are new:
534 datarootdir read-only architecture-independent data root [PREFIX/share]
535 localedir locale-specific message catalogs [DATAROOTDIR/locale]
536 docdir documentation root [DATAROOTDIR/doc/PACKAGE]
537 htmldir html documentation [DOCDIR]
538 dvidir dvi documentation [DOCDIR]
539 pdfdir pdf documentation [DOCDIR]
540 psdir ps documentation [DOCDIR]
542 The following variables have new default values:
544 datadir read-only architecture-independent data [DATAROOTDIR]
545 infodir info documentation [DATAROOTDIR/info]
546 mandir man documentation [DATAROOTDIR/man]
548 This means that if you use any of `@datadir@', `@infodir@', or
549 `@mandir@' in a file, you will have to ensure `${datarootdir}' is
550 defined in this file. As a temporary measure, if any of those are
551 found but no mention of `datarootdir', the substitutions will be
552 replaced with values that do not contain `${datarootdir}', and a
553 warning will be issued.
555 ** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
556 a trailing slash. Similar change will be made to ac_top_builddir in a
557 future release; the old style value, which matches (../)*, is (and will
558 continue to be) available as ac_top_build_prefix.
561 New macro to check for support of 'typeof' syntax a la GNU C.
563 ** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
564 New "once-only" variants of commonly-used macros, to make 'configure'
565 smaller and faster in common cases.
568 New macro to check for strtold with C99 semantics.
571 New macro that lets builder disable assertions at 'configure'-time.
574 Now checks for X11/Xlib.h and XrmInitialize (X proper) rather than
575 X11/Intrinsic.h and XtMalloc (Xt).
577 ** AC_PRESERVE_HELP_ORDER
578 New macro that causes `configure' to display help strings for AC_ARG_ENABLE
579 and AC_ARG_WITH arguments in one region, in the order defined. The default
580 behavior is to group options of each classes separately.
582 ** AC_PROG_CC, AC_PROG_CXX
583 No longer automatically arrange to declare the 'exit' function of C,
584 when a C++ compiler is used. Standard Autoconf macros no longer use
585 'exit', so this is no longer an issue for them. If you use C++, and
586 want to call 'exit', you'll have to arrange for its declaration
587 yourself. But we now suggest you return from 'main' instead.
589 ** AC_PROG_CC_C89, AC_PROG_CC_C99
590 New macros for ISO C99 support. AC_PROG_CC_C89 and AC_PROG_CC_C99
591 check for ANSI C89 and ISO C99 support respectively.
594 Has been unobsoleted, and will check if the compiler supports ISO
595 C99, falling back to ANSI C89 if not. ac_cv_prog_cc_stdc is
596 retained for backwards compatibility, assuming the value of
597 ac_cv_prog_cc_c99 or ac_cv_prog_cc_c89 (whichever is valid, in
600 ** AC_STRUCT_DIRENT_D_INO, AC_STRUCT_DIRENT_D_TYPE
601 New macros for checking commonly-used members of struct dirent.
604 The substituted value can now contain newlines.
607 The substitution now occurs only when @variable@ is on a line by itself,
608 optionally surrounded by spaces and tabs. The whole line is replaced.
610 ** AC_TYPE_LONG_DOUBLE, AC_TYPE_LONG_DOUBLE_WIDER
611 New macros to check for long double, and whether it is wider than double.
612 The old macro AC_C_TYPE_LONG_DOUBLE has been marked as obsolete;
613 applications should switch to the new macro.
615 ** AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, AC_TYPE_INT64_T,
616 AC_TYPE_INTMAX_T, AC_TYPE_INTPTR_T, AC_TYPE_LONG_LONG_INT, AC_TYPE_SSIZE_T,
617 AC_TYPE_UINT8_T, AC_TYPE_UINT16_T, AC_TYPE_UINT32_T, AC_TYPE_UINT64_T,
618 AC_TYPE_UINTMAX_T, AC_TYPE_UINTPTR_T, AC_TYPE_UNSIGNED_LONG_LONG_INT
619 New macros to check for C99 and POSIX types.
621 ** AC_USE_SYSTEM_EXTENSIONS
622 New macro to enable extensions to Posix.
625 New macro which is defined to the name of the first declared config header
626 or undefined if no config headers have been declared yet.
629 The macro correctly handles quadrigraphs now.
631 ** AS_BOURNE_COMPATIBLE, AS_SHELL_SANITIZE, AS_CASE
632 These macros are new or published now.
635 New macro for copyright notices in testsuite files.
637 ** ALLOCA, LIBOBJS, LTLIBOBJS
638 Object names added to these variables are now prefixed with `${LIBOBJDIR}',
639 as in `${LIBOBJDIR}alloca.o'. LIBOBJDIR is meant to be defined from
640 `Makefile.in' in case the object files lie in a different directory.
641 The LIBOBJDIR feature is experimental.
644 Supports --no-recursive now.
646 ** New macros to support Erlang/OTP.
647 New macros for configuring paths to Erlang tools and libraries:
648 AC_ERLANG_PATH_ERLC, AC_ERLANG_NEED_ERLC, AC_ERLANG_PATH_ERL,
649 AC_ERLANG_NEED_ERL, AC_ERLANG_CHECK_LIB, AC_ERLANG_SUBST_ROOT_DIR,
650 AC_ERLANG_SUBST_LIB_DIR.
652 New macros for configuring installation of Erlang libraries:
653 AC_ERLANG_SUBST_INSTALL_LIB_DIR, AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR.
655 ** The manual now mentions Gnulib more prominently.
657 ** New macros to support Objective C.
658 AC_PROG_OBJC, AC_PROG_OBJCPP.
660 * Major changes in Autoconf 2.59b
662 Released 2004-08-20, by Paul Eggert.
665 New macro that computes the default alignment of a type.
667 ** AC_CHECK_TOOL, AC_PATH_TOOL, AC_CHECK_TOOLS
668 When cross-compiling, these macros will give a warning if the tool
669 is not prefixed. In the future, unprefixed cross tools will not
670 be detected; please consult the info documentation for information
671 about the reason of this change.
673 ** AC_CHECK_TARGET_TOOL, AC_PATH_TARGET_TOOL, AC_CHECK_TARGET_TOOLS
674 New macros that detect programs whose name is prefixed with the
675 target type, if the build type and target type are different.
677 ** AC_REQUIRE_AUX_FILE
678 New trace macro that declares expected auxiliary files.
681 New macro that tests for a grep program that accepts as a long a line
684 ** AC_PROG_EGREP, AC_PROG_FGREP
685 These macros now require AC_PROG_GREP, and try EGREP="$GREP -E" and
686 FGREP="$GREP -F" respectively if possible, or else run a path search for
687 a program that accepts as long a line as possible.
690 New macro that tests for a sed program that truncates as few characters
693 * Major changes in Autoconf 2.59
695 Released 2003-11-04, by Akim Demaille
697 ** ac_abs_builddir etc.
698 Absolute file names were actually relative in 2.58.
700 * Major changes in Autoconf 2.58
702 Released 2003-11-04, by Akim Demaille
705 core.* files are no longer removed, as they may be valid user files.
707 ** autoreconf and auxiliary directory
708 Autoreconf creates the auxiliary directory if needed. This is
709 especially useful for initial "bootstrapping" of fresh CVS checkouts.
711 ** AC_CONFIG_MACRO_DIR
712 Use this macro to declare the directory for local M4 macros for aclocal.
715 No longer includes twice the same file in LIBOBJS if invoked
718 ** AC_CONFIG_COMMANDS
719 The directory for its first argument is automatically created. For
722 AC_CONFIG_COMMANDS([src/modules.hh], [...])
724 $top_builddir/src/ is created if needed.
726 ** Autotest and local.at
727 The optional file local.at is always included in Autotest test suites.
730 The warnings are always issued, including with cached runs.
731 This became a significant problem since aclocal and automake can
732 run autoconf behind the scene.
734 ** autoheader warnings
735 The warnings of autoheader can be turned off, using --warning.
736 For instance, -Wno-obsolete disables the complaints about acconfig.h
737 and other deprecated constructs.
740 AC_C_RESTRICT, AC_INCLUDES_DEFAULT, AC_LANG_ASSERT, AC_LANG_WERROR,
743 ** AC_DECL_SYS_SIGLIST
747 Now checks that mktime is the inverse of localtime.
749 ** Improve DJGPP portability
750 The Autoconf tools and configure behave better under DJGPP.
752 ** Present But Cannot Be Compiled
753 New FAQ section dedicated to the mystic
755 configure: WARNING: pi.h: present but cannot be compiled
756 configure: WARNING: pi.h: check for missing prerequisite headers?
757 configure: WARNING: pi.h: proceeding with the preprocessor's result
760 ** Concurrent executions of autom4te
761 autom4te now locks its internal files, which enables concurrent
762 executions of autom4te, likely to happen if automake, autoconf,
763 autoheader etc. are run simultaneously.
766 Use of Libtool 1.5 and higher is encouraged. Compatibility with
767 Libtool pre-1.4 is not checked.
770 Testsuites no longer rerun failed tests in verbose mode; instead,
771 failures are logged while the test is run.
773 In addition, expected failures can be marked as such.
775 * Major changes in Autoconf 2.57
777 Released 2002-12-03 by Paul Eggert.
779 Bug fixes for problems with AIX linker, with freestanding C compilers,
780 with GNU M4 limitations, and with obsolete copies of GNU documents.
782 The Free Documentation License has been upgraded from 1.1 to 1.2.
784 * Major changes in Autoconf 2.56
786 Released 2002-11-15 by Akim Demaille.
788 One packaging problem fixed (config/install-sh was not executable).
790 * Major changes in Autoconf 2.55
792 Released 2002-11-14 by Akim Demaille.
796 Have your configure.ac checked by autoscan ("autoscan").
797 Try the warning options ("autoreconf -fv -Wall").
801 - AC_CHECK_HEADER, AC_CHECK_HEADERS
802 More information on proper use.
804 - Writing Test Programs
806 This sections explains how to write good test sources to use with
807 AC_COMPILE_IFELSE etc. It documents AC_LANG_PROGRAM and so forth.
809 - AC_FOO_IFELSE vs. AC_TRY_FOO
811 Explains why Autoconf moves from AC_TRY_COMPILE etc. to
812 AC_COMPILE_IFELSE and AC_LANG_PROGRAM etc.
816 - Is more robust to different Gettext installations.
818 - Produces messages (when --verbose) to be understood by Emacs'
821 - Supports -W/--warnings.
824 Once the GNU Build System reinstalled, run `./config.status
825 --recheck && ./config.status && make' if possible.
829 - Supports --cache, and --no-cache.
831 - ~/.autom4te.cfg makes it possible to disable the caching mechanism
832 (autom4te.cache). See `Customizing autom4te' in the documentation.
839 Support for the obsoleted options -m, --macrodir, -l, --localdir is
840 dropped in favor of the safer --include/--prepend-include scheme.
845 AC_COMPILER_IFELSE, AC_FUNC_MBRTOWC, AC_HEADER_STDBOOL,
846 AC_LANG_CONFTEST, AC_LANG_SOURCE, AC_LANG_PROGRAM, AC_LANG_CALL,
847 AC_LANG_FUNC_TRY_LINK, AC_MSG_FAILURE, AC_PREPROC_IFELSE.
850 Obsoleted macros are kept for Autoconf backward compatibility, but
851 should be avoided in configure.ac. Running autoupdate is advised.
854 - AC_DEFINE/AC_DEFINE_UNQUOTED
856 We have to stop using the old compatibility scheme --that tried to
857 avoid useless backslashes-- because Libtool 1.4.3 contains a
859 AC_DEFINE([error_t], [int],
860 [Define to a type to use for \`error_t' if it is not
861 otherwise available.])
863 We have to quote the single quotes and backslashes with \. The old
864 compatibility scheme saw that ` was backslashed, and therefore did
865 not quote the single quote... Failure. Hence, Autoconf 2.54 is not
866 compatible with Libtool. Autoconf 2.55 is, but in some cases might
867 produce more \ than wanted.
869 Please, note that in the future the same problem will happen with
870 AC_MSG_*: use `autoreconf -f -Wall'.
874 - Portability of the Autoconf package to Solaris.
876 - Spurious warnings caused by config.status.
877 This bug is benign, but painful: on some systems (typically
878 FreeBSD), warnings such as:
880 config.status: creating Makefile
881 mv: Makefile: set owner/group (was: 1357/0): Operation not permitted
883 could be issued. This is fixed.
886 Simultaneous executions of config.status are possible again.
888 - Precious variables accumulation
890 config.status could stack several copies of the precious variables
894 ** Plans for later versions
898 The compatibility hooks with the old scheme will be completely
899 removed. Please, advice/use `--build', `--host', and `--target'
902 - AC_CHECK_HEADER, AC_CHECK_HEADERS
904 The tests will be stricter, please make sure your invocations are
909 Shell functions will gradually be introduced, probably starting with
910 Autotest. If you know machines which are in use that you suspect
911 *not* to support shell functions, please run the test suite of
912 Autoconf 2.55 on it, and report the results to
913 bug-autoconf@gnu.org.
917 Special characters in AC_MSG_* need not be quoted. Currently,
918 Autoconf has heuristics to decide when a string is escaped, or has
919 to be escaped. This scheme is fragile, and will be removed; the
920 only risk is uglified messages. Please, run `autoreconf -f -Wall'
921 to find occurrences that will be affected.
923 * Major changes in Autoconf 2.54
925 Released 2002-09-13 by Akim Demaille.
929 - autoreconf no longer changes the version of the gettext/po/intl
930 support files. It now adds the files the correspond to the
931 AM_GNU_GETTEXT_VERSION declared in configure.ac.
933 Warning: It now relies on the 'autopoint' program, which is part
934 of GNU gettext 0.11.4 and newer.
936 Please note that you need to have a GNU gettext version that
937 corresponds at least to the AM_GNU_GETTEXT_VERSION declared
938 in configure.ac. You can upgrade to newer GNU gettext versions,
939 though, without needing to change configure.ac.
941 - The -I DIR or --include=DIR option now appends DIR to the include path
942 instead of prepending; this is for consistency with other GNU tools.
943 The new -B DIR or --prepend-include=DIR option has the old behavior.
948 Now handles all the gory details about LIBOBJS and LTLIBOBJS.
949 Please, remove lines such as
951 # This is necessary so that .o files in LIBOBJS are also
952 # built via the ANSI2KNR-filtering rules.
953 LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
955 and read the `AC_LIBOBJ vs LIBOBJS' section. Do not define U in
956 your Makefiles either.
958 - AC_CONFIG_LINKS now makes copies if it can't make links.
960 - AC_FUNC_FNMATCH now tests only for POSIX compatibility, reverting to
961 Autoconf 2.13 behavior. The new macro AC_FUNC_FNMATCH_GNU also
962 tests for GNU extensions to fnmatch, and replaces fnmatch if needed.
964 - AC_FUNC_SETVBUF_REVERSED no longer fails when cross-compiling.
966 - AC_PROG_CC_STDC is integrated into AC_PROG_CC.
968 - AC_PROG_F77 default search no longer includes cf77 and cfg77.
972 AC_C_BACKSLASH_A, AC_CONFIG_LIBOBJ_DIR, AC_GNU_SOURCE,
973 AC_PROG_EGREP, AC_PROG_FGREP, AC_REPLACE_FNMATCH,
974 AC_FUNC_FNMATCH_GNU, AC_FUNC_REALLOC, AC_TYPE_MBSTATE_T.
977 looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
980 Now defines HAVE_MALLOC to 0 if `malloc' does not work, and asks
981 for an AC_LIBOBJ replacement.
985 - Spurious complaints from `m4_bmatch' about invalid regular
986 expressions are suppressed.
988 - Empty top_builddirs are properly handled.
990 - AC_CHECK_MEMBER works correctly when the member is an aggregate.
993 Now colon in the optional path arguments are properly handled.
995 ** Improved portability
997 - Both Autoconf the package, and the scripts it produces, should run
998 more reliably with Zsh. Bear in mind it is the default Bourne shell
1001 - Autoconf and the scripts it produces no longer assume the existence of
1002 the obsolescent commands egrep and fgrep.
1006 - Limitations of Make
1010 The GNATS base moved to
1011 http://bugs.gnu.org/cgi-bin/gnatsweb.pl?database=autoconf
1012 (It is no longer available, though.)
1017 Now contains the list of ouput variables and files (AC_SUBST,
1020 * Major changes in Autoconf 2.53
1022 Released 2002-03-08 by Akim Demaille.
1026 Perl 5.005_03 or later is required: autom4te is written in Perl and is
1027 needed by autoconf. autoheader, autoreconf, ifnames, and autoscan are
1033 Argument requirements, output variables, defined macros.
1034 - M4sugar, M4sh, Autotest
1036 - Double quoting macros
1037 AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
1039 The Autoconf manual is now distributed under the terms of the GNU FDL.
1040 - Section `Hosts and Cross-Compilation'
1041 Explains the rationale for the 2.5x changes in the cross-compilation
1042 chain, and in the relationships between build, host, and target
1044 Emphasizes that `cross-compilation' == `--host is given'.
1045 If you are working on compilers etc., be sure to read this section.
1046 - Section `AC_LIBOBJ vs. LIBOBJS'
1047 Explains why assigning LIBOBJS directly is now an error.
1048 Details how to update the code.
1053 Now used instead of hard coded line numbers.
1054 This eases the comparison of `configure's, and diminishes the
1055 pressure over control version archives.
1056 Automatic replacement for shells that don't support this feature.
1057 - New output variables
1058 @builddir@, @top_builddir@, @abs_srcdir@, @abs_top_srcdir@, @abs_builddir@,
1063 Autoconf and Autotest modes are provided.
1068 New, used by the Autoconf suite to cache and speed up most processing.
1070 Supported by autom4te, autoconf and autoheader.
1072 Replaces --autoconf-dir and --localdir in autoconf, autoheader,
1073 autoupdate, and autoreconf.
1075 No longer passes --cygnus, --foreign, --gnits, --gnu, --include-deps:
1076 automake options are to be given via AUTOMAKE_OPTIONS.
1078 Runs gettextize and libtoolize when appropriate.
1080 --m4dir is no longer supported.
1082 Now runs only in the specified directories, defaulting to `.',
1083 but understands AC_CONFIG_SUBDIRS for dependent directories.
1084 Before, it used to run on all the `configure.ac' found in the
1086 Independent packages are properly updated.
1090 - The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
1092 Under the user pressure, $? is finally available. Probably a mistake.
1093 - AC_F77_LIBRARY_LDFLAGS now supports the HP/UX f90 compiler.
1094 - Precious variables accumulation
1095 config.status could stack several copies of the precious variables
1097 - AC_PATH_PROG and family.
1098 Works properly when given a literal path.
1100 Somewhere since 2.13, the result had been reversed.
1104 - AC_C_BIGENDIAN supports the cross-compiling case.
1105 - AC_C_BIGENDIAN accepts ACTION-IF-TRUE, ACTION-IF-FALSE, and
1106 ACTION-IF-UNKNOWN arguments. All are facultative, and the default
1107 for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
1109 - AC_C_LONG_DOUBLE now succeeds only if `long double' has more range or
1110 precision than `double'.
1115 It now defines the preprocessor symbols PACKAGE_NAME,
1116 PACKAGE_TARNAME, PACKAGE_VERSION, PACKAGE_STRING, and
1120 Admits a fourth optional parameter: the tar name.
1122 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS.
1123 Provide the user with srcdir, ac_srcdir, ac_top_srcdir, ac_builddir,
1124 ac_top_builddir, ac_abs_srcdir, ac_abs_top_srcdir, ac_abs_builddir,
1125 ac_abs_top_builddir.
1127 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS and AC_OUTPUT.
1128 Are much less expensive when using long lists of files.
1131 Works with shell variables, and non alphanumeric names.
1135 - AC_FUNC_STRERROR_R now sets STRERROR_R_CHAR_P, not HAVE_WORKING_STRERROR_R,
1136 because POSIX 1003.1-200x draft 7 says strerror_r returns int, not char *.
1138 - AC_FUNC_STRTOD substitutes POW_LIB.
1143 * Major changes in Autoconf 2.52
1145 Released 2001-07-18 by Akim Demaille.
1150 This feature was present in autoconf 2.50 but was not documented.
1151 For example, `@<:@' is translated to `[' just before output. This
1152 is useful when writing strings that contain unbalanced quotes, or
1153 other hard-to-quote constructs.
1154 - m4_pattern_forbid, m4_pattern_allow
1155 - Tips for upgrading from 2.13.
1156 - Using autoscan to maintain a configure.ac.
1159 - Now include stdint.h.
1160 - sys/types.h and sys/stat.h are guarded.
1161 - strings.h is included if available, and not conflicting with string.h.
1164 - The test suite is more robust and presents less false failures.
1165 - Invocation of GNU M4 now robust to POSIXLY_CORRECT.
1166 - configure accepts --prefix='' again.
1167 - AC_CHECK_LIB works properly when its first argument is not a
1169 - HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
1170 - build_, host_, and target_alias are AC_SUBST as in 2.13.
1171 - AC_ARG_VAR properly propagates precious variables inherited from the
1172 environment to ./config.status.
1173 - Using --program-suffix/--program-prefix is portable.
1174 - Failures to detect the default compiler's output extension are less
1176 - `config.status foo' works properly when `foo' depends on variables
1177 set in an AC_CONFIG_THING INIT-CMD.
1178 - autoheader is more robust to broken input.
1179 - Fixed Fortran name-mangling and link tests on a number of systems,
1180 e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
1183 - AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
1184 specify pre-includes. In this case, the headers are compiled with
1185 cc, not merely preprocessed by cpp. Therefore it is the _usability_
1186 of a header which is checked for, not just its availability.
1187 - AC_ARG_VAR refuses to run configure when precious variables have
1189 - Versions of compilers are dumped in the logs.
1190 - AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
1193 - AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
1194 - AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
1195 - AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
1196 AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
1197 Be sure to read `Upgrading from Version 2.13' to understand why
1198 running `autoupdate' is needed.
1199 - AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
1200 a main-like routine is required/possible when linking C/C++ with
1201 Fortran. Users of e.g. AC_F77_WRAPPERS should be aware of these.
1202 - AC_FUNC_GETPGRG behaves better when cross-compiling.
1204 * Major changes in Autoconf 2.51
1205 There was no release of Autoconf 2.51 since some packagers had used
1206 this version number without permission to ship intermediary versions
1207 of 2.50. The version was skipped to avoid confusion.
1209 * Major changes in Autoconf 2.50
1211 Released 2001-05-21 by Akim Demaille.
1213 ** Lots of bug fixes
1214 There have been far too many to enumerate them here. Check out
1215 ChangeLog if you really want to know more.
1217 ** Improved documentation
1218 In particular, portability issues are better covered.
1221 All the standard GNU Makefile targets are supported. The layout has
1222 changed: m4/ holds the M4 extensions Autoconf needs for its
1223 configuration, doc/ contains the documentation, and tests/ contains
1226 ** Man pages are provided
1227 For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
1228 config.guess, config.sub.
1232 Provides a safe and powerful means to trace the macro uses. This
1233 provide the parsing layer for tools which need to `study'
1237 Specify what category of warnings should be enabled.
1239 - When recursing into subdirectories, try for configure.gnu before
1240 configure to adapt for packages not using autoconf on case-insensitive
1244 More errors are now caught (circular AC_REQUIRE dependencies,
1245 AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
1246 etc.). In addition, their location and call stack are given.
1249 autoupdate is much more powerful, and is able to provide the glue code
1250 which might be needed to move from an old macro to its newer
1253 You are strongly encouraged to use it to modernize both your
1254 `configure.in' and your .m4 extension files.
1257 The internal machinery of autoheader has completely changed. As a
1258 result, using `acconfig.h' should be considered to be obsoleted, and
1259 you are encouraged to get rid of it using the AH macros.
1264 ** Fortran 77 compilers
1265 Globally, the support for Fortran 77 is considerably improved.
1267 Support for automatically determining a Fortran 77 compiler's
1268 name-mangling scheme. New CPP macros F77_FUNC and F77_FUNC_ are
1269 provided to wrap C/C++ identifiers, thus making it easier and more
1270 transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
1271 call C/C++ routines. See the Texinfo documentation for details.
1274 The test suite no longer uses DejaGNU. It should be easy to submit
1275 test cases in this new framework.
1278 - --help, --help=long, -hl
1279 no longer dumps useless items.
1281 lists only specific options.
1282 - --help=recursive, -hr
1283 displays the help of all the embedded packages.
1284 - Remembers environment variables when reconfiguring.
1285 The previous scheme to set envvar before running configure was
1287 what prevented configure from remembering the environment in which
1288 it was run, therefore --recheck was run in an inconsistent
1289 environment. Now, one should run
1291 and then --recheck will work properly. Variables declared with
1292 AC_ARG_VAR are also preserved.
1294 $build defaults to `config.guess`, $host to $build, and then $target
1296 Cross-compilation is a global status of the package, it no longer
1297 depends upon the current language.
1298 Cross compilation is enabled iff the user specified `--host'.
1299 `configure' now fails if it can't run the executables it compiles,
1300 unless cross-compilation is enabled.
1302 The cache file is disabled by default. The new options
1303 `--config-cache', `-C' set the cache to `config.cache'.
1307 Much faster on most architectures.
1308 - concurrent executions
1309 It is safe to use `make -j' with config.status.
1310 - human interface improved
1311 It is possible to invoke
1312 ./config.status foobar
1313 instead of the former form (still valid)
1314 CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
1315 CONFIG_FILES=foobar:foo.in:bar.in \
1317 The same holds for configuration headers and links.
1318 You can instantiate unknown files and headers:
1319 ./config.status --header foo.h:foo.h.in --file bar:baz
1320 - has a useful --help
1321 - accepts special file name "-" for stdin/stdout
1326 Specify additional copyright information.
1329 Now expects the identity of the package as argument.
1333 Most macros, if not all, now strictly follow the `one quotation
1334 level' rule. This results in a more predictable expansion.
1337 A sly bug in the AC_REQUIRE machinery, which could produce incorrect
1338 configure scripts, was fixed by Axel Thimm.
1342 Document and ask for the registration of an envvar.
1345 Specifies the file which `configure' should look for when trying to
1346 find the source tree (used to be handled by AC_INIT).
1348 - AC_CONFIG_COMMANDS
1349 To add new actions to config.status. Should be used instead of
1353 Replaces AC_LINK_FILES.
1355 - AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
1356 AC_CONFIG_LINKS, and AC_CONFIG_FILES
1357 They now obey sh: you should no longer use shell variables as
1358 argument. Instead of
1360 test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
1361 AC_CONFIG_SUBDIRS($my_subdirs)
1365 if test "$package_foo_enabled" = yes; then
1366 AC_CONFIG_SUBDIRS(foo)
1370 To format an Autoconf macro's help string so that it looks pretty
1371 when the user executes `configure --help'.
1374 ** Generic Test Macros
1376 The interface of the AC_CHECK families of macros (decl, header,
1377 type, member, func) is now uniform. They support the same set of
1380 - AC_CHECK_DECL, AC_CHECK_DECLS
1381 To check whether a symbol is declared.
1383 - AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
1384 No longer need a cross-compilation default.
1387 The test it performs is much more robust than previously, and makes
1388 it possible to test builtin types in addition to typedefs.
1389 It is now schizophrenic:
1390 - AC_CHECK_TYPE(TYPE, REPLACEMENT)
1391 remains for backward compatibility, but its use is discouraged.
1392 - AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
1393 behaves exactly like the other AC_CHECK macros.
1396 Checks whether given types are supported by the system.
1398 - AC_CHECK_MEMBER, AC_CHECK_MEMBERS
1399 Check for given members in aggregates (e.g., pw_gecos in struct
1403 Checks if the compiler supports ISO C, included when needs special
1407 Checking whether the preprocessor indicates missing includes by the
1408 error code. stderr is checked by AC_TRY_CPP only as a fallback.
1411 Takes a language as argument and replaces AC_LANG_C,
1412 AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
1414 - AC_LANG_PUSH, AC_LANG_POP
1415 Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
1418 - AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
1419 AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
1420 AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
1424 Sets GETGROUPS_LIBS.
1426 - AC_FUNC_GETLOADAVG
1427 Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
1430 Now integrates `AC_DECL_YYTEXT' which is obsoleted.
1433 Arrange for large-file support.
1435 - AC_EXEEXT, AC_OBJEXT
1436 You are no longer expected to use them: their computation is
1437 performed by default.
1439 ** C++ compatibility
1440 Every macro has been revisited in order to support at best CC=c++.
1442 Major changes in Autoconf 2.14:
1443 There was no release of GNU Autoconf 2.14.
1445 Major changes in Autoconf 2.13:
1447 Released 1999-05-01 by Ben Elliston.
1449 * Support for building on Win32 systems where the only available C or
1450 C++ compiler is the Microsoft Visual C++ command line compiler
1451 (`cl'). Additional support for building on Win32 systems which are
1452 using the Cygwin or Mingw32 environments.
1453 * Support for alternative object file and executable file extensions.
1454 On Win32, for example, these are .obj and .exe. These are discovered
1455 using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
1456 @EXEEXT@ in the output, respectively.
1457 * New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
1458 AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
1459 AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
1460 * AC_DEFINE now has an optional third argument for a description to be
1461 placed in the config header input file (e.g. config.h.in).
1462 * The C++ code fragment compiled for the C++ compiler test had to be
1463 improved to include an explicit return type for main(). This was
1464 causing failures on systems using recent versions of the EGCS C++
1466 * Fixed an important bug in AC_CHECK_TYPE that would cause a configure
1467 script to report that `sometype_t' was present when only `type_t'
1469 * Merge of the FSF version of config.guess and config.sub to modernize
1470 these scripts. Add support for a few new hosts in config.guess.
1471 Incorporate latest versions of install-sh, mkinstalldirs and
1472 texinfo.tex from the FSF.
1473 * autoreconf is capable of running automake if necessary (and
1475 * Support for Fortran 77. See the Texinfo documentation for details.
1476 * Bug fixes and workarounds for quirky bugs in vendor utilities.
1478 Major changes in Autoconf 2.12:
1480 Released 1996-11-26 by David J. MacKenzie
1482 * AC_OUTPUT and AC_CONFIG_HEADER can create output files by
1483 concatenating multiple input files separated by colons, like so:
1484 AC_CONFIG_HEADER(config.h:conf.pre:config.h.in:conf.post)
1485 AC_OUTPUT(Makefile:Makefile.in:Makefile.rules)
1486 The arguments may be shell variables, to compute the lists on the fly.
1487 * AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
1488 * New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
1491 Major changes in Autoconf 2.11:
1493 Released November 18th, 1996, by David J. MacKenzie
1495 * AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
1496 They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
1497 * AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
1498 * AC_CONFIG_HEADER expands shell variables in its argument.
1499 * New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
1500 * The "checking..." messages and the source code for test programs that
1501 fail are saved in config.log.
1502 * Another workaround has been added for seds with small command length limits.
1503 * config.sub and config.guess recognize more system types.
1506 Major changes in Autoconf 2.10:
1508 Released May 7th, 1996, by Roland McGrath
1511 * The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
1512 changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
1514 Major changes in Autoconf 2.9:
1516 Released March 16th, 1996, by Roland McGrath
1520 Major changes in Autoconf 2.8:
1522 Released March 8th, 1996, by Roland McGrath
1526 Major changes in Autoconf 2.7:
1528 Released November 22nd, 1995, by David J. MacKenzie
1532 Major changes in Autoconf 2.6:
1534 Released November 20th, 1995, by David J. MacKenzie
1538 Major changes in Autoconf 2.5:
1540 Released November 17th, 1995, by Roland McGrath
1542 * New configure options --bindir, --libdir, --datadir, etc., with
1543 corresponding output variables.
1544 * New macro: AC_CACHE_CHECK, to make using the cache easier.
1545 * config.log contains the command being run as well as any output from it.
1546 * AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
1547 * AC_PROG_INSTALL doesn't cache a name for install-sh, for sharing caches.
1548 * AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
1549 AC_CHECK_TOOL can search a path other than $PATH.
1550 * AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
1552 Major changes in Autoconf 2.4:
1554 Released June 14th, 1995, by David J. MacKenzie
1556 * Fix a few bugs found by Emacs testers.
1558 Major changes in Autoconf 2.3:
1560 Released March 27th, 1995, by David J. MacKenzie
1562 * Fix the cleanup trap in several ways.
1563 * Handle C compilers that are picky about option placement.
1564 * ifnames gets the version number from the right directory.
1566 Major changes in Autoconf 2.2:
1568 Released March 8th, 1995, by David J. MacKenzie
1570 * The ifnames utility is much faster but requires a "new awk" interpreter.
1571 * AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
1572 library before existing libs, not after, in case it uses them.
1573 * New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
1574 * Lots of bug fixes.
1575 * Many additions to the TODO file :-)
1577 Major changes in Autoconf 2.1:
1579 Released November 4th, 1994, by David J. MacKenzie
1582 * More explanations in the manual.
1583 * Fix a spurious failure in the testsuite.
1584 * Clarify some warning messages.
1585 * autoreconf by default only rebuilds configure and config.h.in files
1586 that are older than any of their particular input files; there is a
1587 --force option to use after installing a new version of Autoconf.
1589 Thanks to everybody who's submitted changes and additions to Autoconf!
1590 I've incorporated many of them, and am still considering others for
1591 future releases -- but I didn't want to postpone this release indefinitely.
1593 Caution: don't indiscriminately rebuild configure scripts with
1594 Autoconf version 2. Some configure.in files need minor adjustments to
1595 work with it; the documentation has a chapter on upgrading. A few
1596 configure.in files, including those for GNU Emacs and the GNU C
1597 Library, need major changes because they relied on undocumented
1598 internals of version 1. Future releases of those packages will have
1599 updated configure.in files.
1601 It's best to use GNU M4 1.3 (or later) with Autoconf version 2.
1602 Autoconf now makes heavy use of M4 diversions, which were implemented
1603 inefficiently in GNU M4 releases before 1.3.
1605 Major changes in Autoconf 2.0:
1607 Released October 26th, 1994, by David J. MacKenzie
1609 ** New copyright terms:
1610 * There are no restrictions on distribution or use of configure scripts.
1613 * Autoconf manual is reorganized to make information easier to find
1614 and has several new indexes.
1615 * INSTALL is reorganized and clearer and is now made from Texinfo source.
1618 * autoscan to generate a preliminary configure.in for a package by
1619 scanning its source code for commonly used nonportable functions,
1620 programs, and header files.
1621 * ifnames to list the symbols used in #if and #ifdef directives in a
1623 * autoupdate to update a configure.in to use the version 2 macro names.
1624 * autoreconf to recursively remake configure and configuration header
1625 files in a source tree.
1627 ** Changed utilities:
1628 * autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
1629 * autoconf and autoheader can look for package-local definition files
1630 in an alternate directory.
1633 * AC_CACHE_VAL to share results of tests between configure runs.
1634 * AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
1635 that macros invoked with AC_REQUIRE don't interrupt other macros.
1636 * AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
1637 support deciding unguessable features based on the host and target types.
1638 * AC_CONFIG_SUBDIRS to recursively configure a source tree.
1639 * AC_ARG_PROGRAM to use the options --program-prefix,
1640 --program-suffix, and --program-transform-name to change the names
1641 of programs being installed.
1642 * AC_PREFIX_DEFAULT to change the default installation prefix.
1643 * AC_TRY_COMPILE to compile a test program without linking it.
1644 * AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
1645 * AC_CHECK_LIB to check for a particular function and library.
1646 * AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
1647 whether or not the test succeeds. They obsolete AC_CHECKING and AC_VERBOSE.
1648 * AC_SUBST_FILE to insert one file into another.
1649 * AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
1650 * AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
1651 * AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
1652 * AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
1655 * Many macros renamed systematically, but old names are accepted for
1656 backward compatibility.
1657 * AC_OUTPUT adds the "automatically generated" comment to
1658 non-Makefiles where it finds @configure_input@ in an input file, to
1659 support files with various comment syntaxes.
1660 * AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
1661 files when they are not enclosed in @ signs.
1662 * AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
1663 override the file name "config.status".
1664 * AC_OUTPUT takes an optional argument for passing variables from
1665 configure to config.status.
1666 * AC_OUTPUT and AC_CONFIG_HEADER allow you to override the input-file names.
1667 * AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
1668 CPPFLAGS, and LDFLAGS from the environment.
1669 * AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
1670 * AC_PROG_INSTALL looks for install-sh or install.sh in the directory
1671 specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
1672 srcdir/../.. by default.
1673 * AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
1674 * AC_DEFINE no longer prints anything, because of the new result reporting
1675 mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
1676 * AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
1677 * AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
1678 --enable- and --with- options.
1679 * AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
1680 execute on success or failure.
1681 * Checking for C functions in C++ works.
1684 * AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
1685 better maintained with them.
1686 * AC_ARG_ARRAY removed because no one was likely using it.
1687 * AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
1688 take arguments, for consistency with all of the other specific checks.
1691 * Comes with config.sub and config.guess, and uses them optionally.
1692 * Uses config.cache to cache test results. An alternate cache file
1693 can be selected with the --cache-file=FILE option.
1694 * Uses optional shell scripts $prefix/share/config.site and
1695 $prefix/etc/config.site to perform site or system specific initializations.
1696 * configure saves compiler output to ./config.log for debugging.
1697 * New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
1698 * acsite.m4 is the new name for the system-wide aclocal.m4.
1699 * Has a DejaGnu test suite.
1701 Major changes in Autoconf 1.11:
1703 * AC_PROG_INSTALL calls install.sh with the -c option.
1704 * AC_SET_MAKE cleans up after itself.
1705 * AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
1706 * AC_OUTPUT prevents shells from looking in PATH for config.status.
1708 Plus a few other bug fixes.
1710 Major changes in Autoconf 1.10:
1712 * autoheader uses config.h.bot if present, analogous to config.h.top.
1713 * AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
1715 * AC_PROG_CXX looks for cxx as a C++ compiler.
1717 Plus several bugs fixed.
1719 Major changes in Autoconf 1.9:
1721 * AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
1722 * AC_SIZEOF_TYPE generates the cpp symbol name automatically,
1723 and autoheader generates entries for those names automatically.
1724 * AC_FIND_X gets the result from xmkmf correctly.
1725 * AC_FIND_X assumes no X if --without-x was given.
1726 * AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
1727 * AC_PROG_INSTALL finds OSF/1 installbsd.
1729 Major changes in Autoconf 1.8:
1732 * New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
1733 AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
1734 for checking both C++ and C features in one configure script.
1735 * New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
1736 * New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
1737 AC_SET_MAKE, AC_ENABLE.
1740 * AC_FIND_X looks for X in more places.
1741 * AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
1742 install.sh is distributed with Autoconf.
1743 * AC_DECLARE_YYTEXT has been removed because it can't work, pending
1744 a rewrite of quoting in AC_DEFINE.
1745 * AC_OUTPUT adds its comments in C format when substituting in C files.
1746 * AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
1748 ** New or changed command line options:
1749 * configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
1750 * configure accepts --without-PACKAGE, which sets withval=no.
1751 * configure accepts --x-includes=DIR and --x-libraries=DIR.
1752 * Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
1753 * configure accepts --help, --version, --silent/--quiet, --no-create options.
1754 * configure accepts and ignores most other Cygnus configure options, and
1755 warns about unknown options.
1756 * config.status accepts --help, --version options.
1758 ** File names and other changes:
1759 * Relative srcdir values are not made absolute.
1760 * The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
1761 * Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
1762 * autoheader optionally copies config.h.top to the beginning of config.h.in.
1763 * The example Makefile dependencies for configure et al. work better.
1764 * Namespace cleanup: all shell variables used internally by Autoconf
1765 have names beginning with `ac_'.
1767 More big improvements are in process for future releases, but have not
1768 yet been (variously) finished, integrated, tested, or documented enough
1771 Major changes in Autoconf 1.7:
1773 * New macro AC_OBSOLETE.
1774 * Bugs in Makefile.in fixed.
1775 * AC_LONG_FILE_NAMES improved.
1777 Major changes in Autoconf 1.6:
1779 * New macro AC_LONG_64_BITS.
1780 * Multiple .h files can be created.
1781 * AC_FIND_X looks for X files directly if it doesn't find xmkmf.
1782 * AC_ALLOCA defines C_ALLOCA if using alloca.c.
1783 * --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
1784 * Unused --no-create option to configure removed.
1785 * autoheader doesn't change the timestamp of its output file if
1786 the file didn't change.
1787 * All macros that look for libraries now use AC_HAVE_LIBRARY.
1788 * config.status checks three optional environment variables to
1789 modify its behavior.
1790 * The usual bug fixes.
1792 Major changes in Autoconf 1.5:
1794 * New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
1795 * autoconf and autoheader scripts have GNU standards conforming
1796 --version and --help options (they print their message and exit).
1799 Major changes in Autoconf 1.4:
1801 * New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
1802 AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
1803 * autoconf and autoheader use the M4 environment variable to determine the
1804 name of the M4 program to use.
1805 * The --macrodir option to autoconf and autoheader specifies the directory
1806 in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
1807 * autoconf and autoheader can take `-' as their file names, which means to
1808 read stdin as input.
1809 * Resulting configure scripts can take a --verbose option which causes them
1810 to print the results of their tests.
1811 * AC_DEFINE quotes its second argument in such a way that spaces, magic
1812 shell characters, etc. will be preserved during various stages of
1813 expansion done by the shell. If you don't want this, use
1814 AC_DEFINE_UNQUOTED instead.
1815 * Much textual processing done with external calls to tr and sed have been
1816 internalized with builtin M4 `patsubst' and `translit' calls.
1817 * AC_OUTPUT doesn't hardwire the file names it outputs. Instead, you can
1818 set the shell variables `gen_files' and `gen_config' to the list of
1819 file names to output.
1820 * AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
1821 "lex.yy" or "lexyy", depending on the system.
1822 * AC_PROGRAMS_CHECK takes an optional third arg. If given, it is used as
1824 * If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
1825 * AC_CONST works much more reliably on more systems.
1828 Major changes in Autoconf 1.3:
1830 configure no longer requires awk for packages that use a config.h.
1831 Support handling --with-PACKAGE options.
1832 New `autoheader' script to create `config.h.in' from `configure.in'.
1833 Ignore troublesome -lucb and -lPW when searching for alloca.
1834 Rename --exec_prefix to --exec-prefix for GNU standards conformance.
1835 Improve detection of STDC library.
1836 Add AC_HAVE_LIBRARY to check for non-default libraries.
1837 Function checking should work with future GNU libc releases.
1839 Major changes in Autoconf 1.2:
1841 The --srcdir option is now usually unnecessary.
1842 Add a file containing sample comments describing CPP macros.
1843 A comment in config.status tells which host it was configured on.
1844 Substituted variable values can now contain commas.
1845 Fix bugs in various feature checks.
1847 Major changes in Autoconf 1.1:
1849 Added AC_STRCOLL macro.
1850 Made AC_GETLOADAVG check for more things.
1851 AC_OUTPUT argument is now optional.
1856 Copyright (C) 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002,
1857 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
1859 This program is free software: you can redistribute it and/or modify
1860 it under the terms of the GNU General Public License as published by
1861 the Free Software Foundation, either version 3 of the License, or
1862 (at your option) any later version.
1864 This program is distributed in the hope that it will be useful,
1865 but WITHOUT ANY WARRANTY; without even the implied warranty of
1866 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1867 GNU General Public License for more details.
1869 You should have received a copy of the GNU General Public License
1870 along with this program. If not, see <http://www.gnu.org/licenses/>.