1 GNU Autoconf NEWS - User visible changes.
3 * Noteworthy changes in release ?.? (????-??-??) [?]
6 * Noteworthy changes in release 2.68 (2010-09-22) [stable]
7 Released by Eric Blake, based on git versions 2.67.*.
9 ** AC_MSG_ERROR (and AS_ERROR) can once again be followed immediately by
10 `dnl'. Regression introduced in 2.66.
12 ** AC_INIT again allows URLs with '?' for its BUG-REPORT argument.
13 Regression introduced in 2.66.
15 ** AC_REPLACE_FUNCS again allows a non-literal argument, such as a shell
16 variable that expands to a list of functions to check. Regression
19 ** AT_BANNER() with empty argument will cause visual separation from previous
22 ** The macros AC_PREPROC_IFELSE, AC_COMPILE_IFELSE, AC_LINK_IFELSE, and
23 AC_RUN_IFELSE now warn if the first argument failed to use
24 AC_LANG_SOURCE or AC_LANG_PROGRAM to generate the conftest file
25 contents. A new macro AC_LANG_DEFINES_PROVIDED exists if you have
26 a compelling reason why you cannot use AC_LANG_SOURCE but must
29 ** The macro m4_define_default is now documented.
31 ** Symlinked config.cache files are supported; configure now tries to
32 update non-symlinked cache files atomically, so that concurrent configure
33 runs do not leave behind broken cache files. It is still unspecified
34 which subset or union of results is cached though.
36 ** Autotest testsuites should not contain long text lines any more, and be
37 portable even when very many test groups are used.
39 ** AT_CHECK semantics with respect to the Autotest variable $at_status and
40 shell execution environment of the arguments are documented now.
42 ** AC_FC_LIBRARY_LDFLAGS now tolerates output from newer gfortran.
44 ** Newly obsolete macros
45 The following macros have been marked obsolete. New programs
46 should use the corresponding Gnulib modules. Gnulib not only
47 detects a larger set of portability problems with these functions,
48 but also provides complete workarounds.
50 AC_FUNC_ERROR_AT_LINE AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK
51 AC_FUNC_MKTIME AC_FUNC_STRTOD
54 * Major changes in Autoconf 2.67 (2010-07-21) [stable]
55 Released by Eric Blake, based on git versions 2.66.*.
57 ** AC_CONFIG_SUBDIRS with more than one subdirectory at a time works again.
58 Regression introduced in 2.66.
60 ** AC_CHECK_SIZEOF of a pointer type works again. Regression introduced in
63 ** New macro AC_FC_LINE_LENGTH to accept long Fortran source code lines.
65 ** AC_PREPROC_IFELSE now keeps the preprocessed output in the conftest.i
66 file for inspection by the commands in the ACTION-IF-TRUE argument.
68 ** AC_INIT again allows parentheses and other characters that are literal
69 in single- or double-quoted strings, and in quoted and unquoted
70 here-documents, for its PACKAGE and VERSION arguments. Regression
73 ** autoreconf passes warning flags to new enough versions of aclocal.
75 ** Running an Autotest testsuite in parallel mode no longer triggers a
76 race condition that could cause the testsuite run to end early,
77 fixing a sporadic failure in autoconf's own testsuite. Bug present
78 since introduction of parallel tests in 2.63b.
81 * Major changes in Autoconf 2.66 (2010-07-02) [stable]
82 Released by Eric Blake, based on git versions 2.65.*.
84 ** AC_FUNC_MMAP works in C++ mode again. Regression introduced in 2.65.
86 ** Use of m4_divert without a named diversion now issues a syntax warning,
87 since it is seldom right to change diversions behind autoconf's back.
89 ** The macros AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, and
90 AC_TYPE_INT64_T work again. Regression introduced in 2.65.
92 ** AC_PROG_INSTALL correctly uses `shtool' again. Regression introduced
95 ** Autoconf should work on EBCDIC hosts.
97 ** AC_CHECK_DECL and AC_CHECK_DECLS accept optional function argument types
98 for overloaded C++ functions.
100 ** AS_SET_CATFILE accepts nonliterals in its variable name argument now.
102 ** Autotest testsuites accept an option --recheck to rerun tests that
103 failed or passed unexpectedly during the last non-debug testsuite run.
105 ** AC_ARG_ENABLE and AC_ARG_WITH now also accept `+' signs in `--enable-*'
106 and `--with-*' arguments, converting them to underscores for the variable
109 ** In configure scripts, loading CONFIG_SITE no longer searches PATH,
110 and problems in loading the configuration site files are diagnosed.
112 ** Autotest testsuites may optionally provide colored test results.
114 ** The previously undocumented Autotest macros AT_ARG_OPTION and
115 AT_ARG_OPTION_ARG have seen bug fixes and are documented now.
116 AT_ARG_OPTION has been changed in that the negative of a long option
117 --OPTION is now --no-OPTION rather than --noOPTION.
119 ** The macro AS_LITERAL_IF is slightly more conservative; text
120 containing shell quotes are no longer treated as literals.
121 Furthermore, a new macro, AS_LITERAL_WORD_IF, adds an additional
122 level of checking that no whitespace occurs in literals.
124 ** The macros AS_TR_SH and AS_TR_CPP no longer expand their results.
126 ** The following macros are now documented:
129 ** New macro AC_FC_FIXEDFORM to accept fixed-form Fortran.
132 * Major changes in Autoconf 2.65 (2009-11-21) [stable]
133 Released by Eric Blake, based on git versions 2.64.*.
135 ** Autoconf is now licensed under the General Public License version 3
136 or later (GPLv3+). As with earlier versions, the license includes
137 an exception clause so that you may release a configure script
138 generated by autoconf under the license of your own program.
140 ** New macros to support Objective C++.
141 AC_PROG_OBJCXX AC_PROG_OBJCXXCPP
143 ** The following undocumented autoconf macros, removed in Autoconf 2.64,
144 have been reinstated:
147 These macros are present only for backwards compatibility purposes.
149 ** The macro AC_LANG_COMPILER no longer fails on embedded systems that
150 lack fopen in the C library, such as AVR or RTEMS (regression
153 ** The AC_FC_FREEFORM macro no longer suffers from a whitespace bug that
154 made it fail with some Fortran compilers (regression introduced in
157 ** The AC_TYPE_UINT64_T and AC_TYPE_INT64_T macros have been fixed to no
158 longer mistakenly select a 32-bit type on some compilers (bug present
159 since macros were introduced in 2.59c).
161 ** The AC_FUNC_MMAP macro has been fixed to be portable to systems like
162 Cygwin (bug present since macro was introduced in 2.0).
164 ** The following documented autotest macros are new:
167 ** The following m4sugar macros now quote their expansion:
168 m4_toupper m4_tolower
170 ** The following m4sugar macros are new:
173 ** The m4sugar macro m4_text_wrap now copes with embedded quoting without
174 requiring quadrigraphs. For uses like AC_ARG_VAR([a], [[b c]]),
175 this gives the intuitive behavior of "[b c]" in the output (2.63
176 gave the output of "[b], [c]", and 2.64 encountered a failure).
178 ** The `$tmp' temporary directory used in config.status is documented for
181 ** config.status now provides a --config option to produce the configuration.
183 ** Many cache variables used by Autoconf's macros are now documented.
185 ** Configure scripts work better on DJGPP by avoiding a bug present in
186 the DJGPP port of bash 2.04 in handling 'return' in a shell
187 function (regression introduced in 2.64).
189 * Major changes in Autoconf 2.64 (2009-07-26) [stable]
190 Released by Eric Blake, based on git versions 2.63b.*.
192 ** Autoconf now requires GNU M4 1.4.6 or later. Earlier versions of M4
193 have a bug in regular expression handling that interferes with some
194 of the speedups provided since Autoconf 2.63. GNU M4 1.4.13 or
195 later is recommended.
197 ** AS_IF and AS_CASE have been taught to avoid syntax errors even when
198 given arguments that expand to just whitespace.
200 ** The following documented autoconf macros are new:
201 AC_ERLANG_SUBST_ERTS_VER
203 ** The autoheader tool now understands m4 macro arguments passed to
204 AC_DEFINE and AC_DEFINE_UNQUOTED.
206 ** Ensure AT_CHECK can support commands that include a # given with
207 proper m4 quoting. For shell comments, this is a new feature; for
208 non-shell comments, this fixes a regression introduced in 2.63b.
209 Additionally, AT_CHECK correctly supplies shell escapes for
210 metacharacters occurring in m4 macro expansions within the expected
211 stdout and stderr parameters.
213 ** The macro AT_CHECK now understands the concept of hard failure. If
214 a test exits with an unexpected status 99, cleanup actions for the
215 test are inhibited and the test is treated as a failure regardless
216 of AT_XFAIL_IF. It also understands the new directives
217 ignore-nolog, stdout-nolog, and stderr-nolog.
219 ** The following documented autotest macros are new:
220 AT_CHECK_UNQUOTED AT_FAIL_IF AT_SKIP_IF
222 ** The following documented m4sugar macros are new:
223 m4_argn m4_copy_force m4_default_nblank m4_default_nblank_quoted
224 m4_ifblank m4_ifnblank m4_rename_force
226 ** The autoconf testsuite now exercises all Erlang macros.
228 * Major changes in Autoconf 2.63b (2009-03-31) [beta]
229 Released by Eric Blake, based on git versions 2.63.*.
231 ** The manual is now shipped under the terms of the GNU FDL 1.3.
233 ** AC_REQUIRE now detects the case of an outer macro which first expands
234 then later indirectly requires the same inner macro. Previously,
235 this case led to silent out-of-order expansion (bug present since
236 2.50); it now issues a syntax warning, and duplicates the expansion
237 of the inner macro to guarantee dependencies have been met. See
238 the manual for advice on how to refactor macros in order to avoid
239 the bug in earlier autoconf versions and avoid increased script
240 size in the current version.
242 ** AC_DEFUN_ONCE has improved semantics. Previously, a macro declared
243 with AC_DEFUN_ONCE warned on a second invocation; and out-of-order
244 expansion was still possible. Now, dependencies are guaranteed,
245 and subsequent invocations are a silent no-op. This makes
246 AC_DEFUN_ONCE an ideal macro for silencing AC_REQUIRE warnings.
248 ** The following macros are now defined with AC_DEFUN_ONCE. This means
249 a subtle change in semantics; previously, an AC_DEFUN macro could
250 expand one of these macros multiple times or surround the macro
251 inside shell conditional text to bypass the effects of these
252 macros, but now the macro will expand exactly once, and prior to
253 the start of any enclosing AC_DEFUN macro:
254 AC_CANONICAL_BUILD AC_CANONICAL_HOST AC_CANONICAL_TARGET
255 AC_HEADER_ASSERT AC_PROG_INSTALL AC_PROG_MKDIR_P
256 AC_USE_SYSTEM_EXTENSIONS
258 ** AC_LANG_ERLANG works once again (regression introduced in 2.61a).
260 ** AC_HEADER_ASSERT is fixed so that './configure --enable-assert' no
261 longer mistakenly disables assertions.
263 ** AC_INIT now takes an optional fifth parameter that can be used to
264 set AC_PACKAGE_URL, a URL for the package's home page; the URL is
265 used in `configure --help' and is also available via AC_DEFINE.
267 ** Autotest testsuites accept an option --jobs[=N] for parallel testing.
268 This feature is still in testing, and may not work on every
269 platform, help in improving it would be appreciated.
271 ** Autotest testsuites do not attempt to write startup error messages
272 to the log file before that is opened (regression introduced in 2.63).
274 ** Configure scripts now use shell functions. This feature leads to
275 smaller configure files and faster execution.
277 ** Present But Cannot Be Compiled: Autoconf will now proceed with
278 the compiler's result if a header is present but cannot be compiled.
279 The warning is still printed, and you should really fix it by
280 providing a fourth parameter to AC_CHECK_HEADER/AC_CHECK_HEADERS.
282 ** Autoreconf added aclocal to the set of programs affected by the
283 `autoreconf -I dir' option.
285 ** The following documented m4sugar macros are new:
286 m4_chomp m4_chomp_all m4_cleardivert m4_curry m4_default_quoted
287 m4_esyscmd_s m4_map_args m4_map_args_pair m4_map_args_sep
288 m4_map_args_w m4_set_map m4_set_map_sep m4_stack_foreach
289 m4_stack_foreach_lifo m4_stack_foreach_sep
290 m4_stack_foreach_sep_lifo
292 ** The following m4sugar macros are documented now, but in some cases
293 with slightly different semantics than what the previous
294 undocumented version had:
295 m4_copy m4_dumpdefs m4_rename m4_version_prereq
297 ** The m4sugar macro m4_expand has been taught to handle unterminated
298 comments and shell case statements. As a result, it is used
299 internally in more places, such as AC_DEFINE and AT_CHECK. Most
300 uses of AC_DEFINE and AT_CHECK should not behave any differently;
301 however, it may be necessary to add double-quoting around
302 unbalanced `(' where single-quoting used to be sufficient.
304 ** The following documented m4sh macros are new:
305 AS_INIT_GENERATED AS_LINENO_PREPARE AS_ME_PREPARE AS_SET_STATUS
306 AS_VAR_APPEND AS_VAR_ARITH AS_VAR_COPY
308 ** The following m4sh macros are documented now, but in some cases
309 with slightly different semantics than what the previous
310 undocumented version had:
311 AS_ECHO AS_ECHO_N AS_ESCAPE AS_EXIT AS_LITERAL_IF AS_UNSET
312 AS_VAR_IF AS_VAR_POPDEF AS_VAR_PUSHDEF AS_VAR_SET AS_VAR_SET_IF
313 AS_VAR_TEST_SET AS_VERSION_COMPARE
315 ** The m4sh macros AS_IF and AS_CASE can now be used in shell lists.
316 The responsibility for supplying a trailing newline now belongs to
317 the call site, but since most users did not add dnl, this generally
318 results in fewer empty lines in configure.
321 * Major changes in Autoconf 2.63 (2008-09-09) [stable]
322 Released by Eric Blake, based on git versions 2.62.*.
324 ** AC_C_BIGENDIAN does not mistakenly report "universal" for some
325 bigendian hosts, a regression introduced with universal binary
328 ** AC_PATH_X now includes /lib64 and /usr/lib64 in its list of default
331 ** AC_USE_SYSTEM_EXTENSIONS no longer conflicts with an external
332 AC_DEFINE([__EXTENSIONS__]). This fixes a regression introduced in
333 2.62 when using macros such as AC_AIX that were made obsolete in
334 favor of the more portable AC_USE_SYSTEM_EXTENSIONS.
336 ** AC_CHECK_TARGET_TOOLS is usable in the non-cross-compile case.
338 ** Newly obsolete macros
339 The following macro has been marked obsolete, since current porting
340 targets can safely assume C89 semantics that signal handlers return
341 void. We have no current plans to remove the macro.
345 ** The macros m4_map and m4_map_sep now ignore any list elements
346 consisting of just empty quotes, and m4_map_sep now expands its
347 separator. This fixes a regression in 2.62 when these macros were
348 first documented, for the sake of clients expecting the semantics
349 that these macros had prior to that time. The new macros m4_mapall
350 and m4_mapall_sep, along with extra quoting of the separator, can
351 be used to get the semantics that m4_map_sep had in 2.62.
353 ** Clients of m4_expand, such as AS_HELP_STRING and AT_SETUP, can now
354 handle properly quoted but otherwise unbalanced parentheses (for
355 some macros, this fixes a regression in 2.62).
357 ** Two new quadrigraphs have been introduced: @{:@ for (, and @:}@ for ),
358 allowing the output of unbalanced parentheses in more contexts.
360 ** The following m4sugar macros are new:
361 m4_cleardivert m4_joinall m4_mapall m4_mapall_sep m4_reverse
362 m4_set_add m4_set_add_all m4_set_contains m4_set_contents
363 m4_set_delete m4_set_difference m4_set_dump m4_set_empty
364 m4_set_foreach m4_set_intersection m4_set_list m4_set_listc
365 m4_set_remove m4_set_size m4_set_union
367 ** The following m4sugar macros now accept multiple arguments, as is the
368 case with underlying m4:
369 m4_defn m4_popdef m4_undefine
371 ** The following m4sugar macros now guarantee linear scaling; they
372 previously had linear scaling with m4 1.6 but quadratic scaling
373 when using m4 1.4.x. All macros built on top of these also gain
374 the scaling improvements.
375 m4_bmatch m4_bpatsubsts m4_case m4_cond m4_do m4_dquote_elt
376 m4_foreach m4_join m4_list_cmp m4_map m4_map_sep m4_max
379 ** AT_KEYWORDS once again performs expansion on its argument, such that
380 AT_KEYWORDS([m4_if([$1], [], [default])]) no longer complains about
381 the possibly unexpanded m4_if [regression introduced in 2.62].
383 ** Config header templates `#undef UNDEFINED /* comment */' do not lead to
384 nested comments any more; regression introduced in 2.62.
387 * Major changes in Autoconf 2.62 (2008-04-05) [stable]
388 Released by Eric Blake, based on git versions 2.61a.*.
390 ** Many optimizations have been applied to make overall execution faster.
392 ** Autotest now makes use of shell functions.
394 ** config.status now uses awk instead of sed also for config headers.
396 - As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
397 values, i.e., backslash-newline combinations are handled correctly.
398 Further, for config headers, the total size of values is not limited by
399 the POSIX length limit of text lines any more, only each single line.
401 ** New config variable `top_build_prefix'.
403 ** New Autoconf macros:
404 AC_AUTOCONF_VERSION AC_OPENMP AC_PATH_PROGS_FEATURE_CHECK
406 ** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.
408 ** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
409 like '__restrict' if the variant spelling is available, as this is
410 more likely to work when mixing C and C++ code.
412 ** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
413 be a string of tokens such that "T y;" is a valid member declaration
416 ** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
417 is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.
419 ** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
420 they did not work for function types. In C++, they now work on any
421 type-id that can be the operand of sizeof; this is similar to C,
422 except it excludes anonymous struct and union types. Formerly,
423 some (but not all) C++ types involving anonymous struct and union
424 were accepted, though this was not documented.
426 ** AC_CONFIG_LINKS now prefers to link against files in the build tree
427 if found, and it works to link against a file of the same name in
428 the source tree, even if both trees coincide.
430 ** AC_INIT no longer alters $@; regression introduced in 2.60.
432 ** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.
434 ** AS_HELP_STRING no longer underquotes its first argument; it also handles
435 the case where the first argument contains single-quoted commas.
436 For example, "AS_HELP_STRING([-a, [--arg[=foo]]], [bar])" produces:
437 " -a, --arg[=foo] bar"
438 Additionally, the macro now takes two additional arguments,
439 indent-column and wrap-column; these should not normally be needed,
440 but can be used to fine-tune how the output text is wrapped.
442 ** AC_PROG_INSTALL now requires an install program that can install multiple
443 files into a target directory.
445 ** The command 'autoconf -' now correctly processes a file from stdin.
447 ** 'autoreconf -m' now honors $MAKE.
449 ** For all of the directory arguments for 'configure', such as '--prefix'
450 or '--bindir', trailing slashes are stripped. As an example, if
451 tab completion in the user's shell appends trailing slashes, the
452 command './configure --prefix=/usr/' will still result in an
453 expanded libdir value of /usr/lib, not /usr//lib.
455 ** `configure --help=recursive' now works in read-only trees and from
456 unconfigured build trees.
458 ** If precious variables differ only in whitespace, then the cache consistency
459 check warns instead of fails, and reuses the old value.
461 ** AT_BANNER is now documented.
463 ** AT_SETUP now handles macro expansions properly when calculating line
466 ** Autotest now determines $srcdir correctly.
468 ** Testsuites built by autotest now accept a -C/--directory=DIR option
469 to adjust the working directory prior to creating files.
471 ** Autoconf now requires GNU M4 1.4.5 or later. Earlier versions of M4 have
472 a bug in macro tracing that interferes with the interaction between
473 Autoconf and Automake. GNU M4 1.4.11 or later is recommended. The
474 configure search for a working M4 is improved.
476 ** For portability with the eventual M4 2.0, macros should no longer use
477 anything larger than $9 to refer to arguments.
479 ** Documentation for m4sugar is improved.
481 - The following macros were previously available as undocumented
482 interfaces; the macros are now documented as stable interfaces.
484 __oline__ m4_assert m4_bmatch m4_bpatsubsts m4_car m4_case
485 m4_cdr m4_default m4_divert_once m4_divert_pop m4_divert_push
486 m4_divert_text m4_do m4_errprintn m4_fatal m4_flatten
487 m4_ifndef m4_ifset m4_ifval m4_ifvaln m4_location
488 m4_n m4_shiftn m4_strip m4_warn
490 - The following macros were previously available as undocumented
491 interfaces, but had bug fixes or semantic changes as part of this
492 release. Packages that relied on the undocumented behavior
493 should be analyzed to make sure they will still work with the
494 new documented behavior.
496 m4_cmp m4_list_cmp m4_join m4_map m4_map_sep m4_sign
497 m4_text_box m4_text_wrap m4_version_compare
499 - The m4_wrap macro used to have unspecified order, but now
500 guarantees FIFO order. m4_wrap_lifo was added to guarantee LIFO
503 - Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
504 should consider using the new AC_AUTOCONF_VERSION instead.
506 - m4sugar macros that are not documented in the manual are still
507 deemed experimental, and should not be used outside of Autoconf.
509 ** The m4sugar macros m4_append and m4_append_uniq, first documented in
510 2.60, have been fixed to treat both the string and the separator
511 arguments consistently with regards to quoting. Prior to this fix,
512 m4_append_uniq could mistakenly duplicate entries if the expansion
513 of the separator resulted in a different string (for example, if it
514 contained quotes, a comma, or a macro name). However, it means
515 that programs previously using
516 m4_append([name], [string], [[, ]])
517 are now using a four-character separator instead of the intended
518 comma and space. If you need portability to earlier versions of
519 Autoconf, you can insert the following snippet after AC_INIT but
520 before any other macro expansions, to enforce the new semantics:
521 m4_pushdef([m4_append], [m4_define([$1],
522 m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
523 Additionally, m4_append_uniq now takes optional parameters that can
524 be used to take action depending on whether anything was appended,
525 and warns if a non-empty separator occurs within the string being
526 appended, since that can lead to duplicates.
528 ** The following m4sugar macros are new:
529 m4_append_uniq_w m4_apply m4_combine m4_cond m4_count
530 m4_dquote_elt m4_echo m4_expand m4_ignore m4_make_list m4_max
531 m4_min m4_newline m4_shift2 m4_shift3 m4_unquote m4_wrap_lifo
533 ** Warnings are now generated by default when an installer invokes
534 'configure' with an unknown --enable-* or --with-* option.
535 These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
536 macro, or by invoking 'configure' with --disable-option-checking.
538 ** Existing obsolete macros
539 The documentation for the following macros is adjusted to make it
540 more clear that they have previously been marked obsolete, as their
541 functionality can be accomplished by other macros. We have no
542 current plans to remove them from Autoconf.
544 AC_ENABLE AC_STRUCT_ST_BLKSIZE AC_STRUCT_ST_RDEV AC_WITH
546 ** Newly obsolete macros
547 The following macros have been marked obsolete, as they only
548 perform a subset of AC_USE_SYSTEM_EXTENSIONS. We have no current
549 plans to remove them.
551 AC_AIX AC_GNU_SOURCE AC_ISC_POSIX AC_MINIX
553 ** AC_C_LONG_DOUBLE is obsolescent.
554 The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
555 tests for problems that are so old that it is no longer of
556 practical importance on current systems. New programs need not use
557 AC_C_LONG_DOUBLE. We have no current plans to remove it.
559 ** AC_DIAGNOSE, AC_WARNING, and AC_FATAL are obsolescent.
560 The documentation now favors the use of M4sugar macros m4_warn and
561 m4_fatal, since the naming makes it more obvious that the
562 diagnostics are associated with M4 expansion (ie. when running
563 `autoconf'), and offers less confusion with the AC_MSG_ERROR,
564 AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
565 when running `configure'. We have no current plans to remove these
569 * Major changes in Autoconf 2.61a (2006-12-11)
571 ** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
572 on many platforms. This has been fixed.
574 ** AC_FUNC_SETVBUF_REVERSED is now obsolete. It is still defined for backward
575 compatibility but it does nothing. The macro was already
576 obsolescent, as the last systems to have the problem were those
577 based on SVR2, which became obsolete in 1987. The macro had bugs
578 on some modern systems and could no longer be maintained reliably
579 due to lack of ancient systems to test it on.
581 ** config.status now uses awk instead of sed for most substitutions, for speed.
583 - As a side effect multi-line values of substituted variables no
584 longer have a small limit in total size, though for portability
585 each line should not exceed the POSIX length limit for text lines.
587 - It is now documented that Makefile.in should not contain
588 overlapping variable occurrences, e.g., @VAR1@VAR2@.
589 Autoconf's behavior was always iffy in such cases, and the
590 awk implementation has changed the behavior.
592 ** Many uses of 'echo' have been rewritten so that Autoconf-generated
593 scripts have fewer problems with strings or file names containing
594 embedded special characters such as backslash or leading "-". This
595 was implemented by using `printf '%s\n' "$foo"' instead of `echo
596 "$foo"' when printf works. Due to the implementation technique
597 used, Autoconf-generated scripts now run considerably more slowly
598 on ancient implementations lacking printf. However, this should
599 not be a problem, since Autoconf-generated scripts in practice
600 invariably find a more-modern shell these days.
603 * Major changes in Autoconf 2.61 (2006-11-17)
605 ** New macros AC_C_FLEXIBLE_ARRAY_MEMBER, AC_C_VARARRAYS.
607 ** AC_ARG_ENABLE and AC_ARG_WITH now allow '.' in feature and package names.
610 * Major changes in Autoconf 2.60b (2006-10-22)
613 Autoconf-generated shell scripts no longer export BIN_SH, due to
614 configuration hassles with this. Installers who need BIN_SH in
615 their environment should set it before invoking 'configure' and
616 'make'. As far as we know, this affects only Unixware installations.
618 ** Obsolescent macros
619 The documentation now says that the following macros are obsolescent,
620 as they are superseded by Gnulib:
622 AC_FUNC_FNMATCH AC_FUNC_FNMATCH_GNU AC_FUNC_GETLOADVG AC_REPLACE_FNMATCH
624 New programs should use the Gnulib counterparts of these macros.
625 We have no current plans to remove them from Autoconf.
627 ** AC_COMPUTE_INT no longer caches or reports results.
629 ** AC_CHECK_DECL now also works with aggregate objects.
631 ** AC_USE_SYSTEM_EXTENSIONS now defines _TANDEM_SOURCE for NonStop platforms.
633 ** GNU M4 1.4.7 or later is now recommended.
636 New M4sugar macro, which is more secure than the POSIX M4 maketemp.
639 Now an alias for m4_mkstemp.
641 * Major changes in Autoconf 2.60a (2006-08-25)
643 ** GNU M4 1.4.6 or later is now recommended.
645 ** The check for C99 now tests for varargs macros, as documented.
646 It also tests that the preprocessor supports 64-bit integers.
648 ** Autoconf now uses constructs like "#ifdef HAVE_STDLIB_H" rather than
649 "#if HAVE_STDLIB_H", so that it now works with "gcc -Wundef -Werror".
651 ** The functionality of the undocumented _AC_COMPUTE_INT is now provided
652 by a public and documented macro, AC_COMPUTE_INT. The parameters to the
653 two macros are different, so autoupdate will not change the old private name
654 to the new one. _AC_COMPUTE_INT may be removed in a future release.
656 ** AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT now require
657 that long long types be at least 64 bits wide, as C99 and tradition
658 requires. Formerly, they accepted implementations of any width.
661 * Major changes in Autoconf 2.60
663 Released 2006-06-23, by Ralf Wildenhues.
665 ** Autoconf no longer depends on whether m4wrap is FIFO (as Posix requires)
666 or LIFO (as in GNU M4 1.4.x). GNU M4 2.0 is expected to conform to Posix
667 here, so m4wrap/m4_wrap users should no longer depend on LIFO behavior.
669 ** Provide a way to turn off warnings about the changed directory variables.
671 * Major changes in Autoconf 2.59d
673 Released 2006-06-05, by Ralf Wildenhues.
675 ** GNU make now recommended for VPATH builds
676 INSTALL now suggests VPATH builds (e.g., "sh ../srcdir/configure")
677 only if you use GNU make. In practice, other 'make' implementations
678 have too many subtle incompatibilities in their support for VPATH.
679 Many packages (including Autoconf itself) are portable to other
680 'make' implementations, but some packages are not, and recommending
681 GNU make keeps the installation instructions simpler.
683 ** Even more safety checks for the new Directory variables:
684 Warn about suspicious `${datarootdir}' found in config files output.
686 ** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
687 These never-documented macros and variables have been marked with
688 comments saying that they may be removed in a future release,
689 because their use can lead to unintended code being executed.
690 If you need functionality that only these macros or variables
691 currently supply, please write bug-autoconf@gnu.org.
693 ** AC_SUBST, AC_DEFINE
694 Literal arguments to these are passed to m4_pattern_allow now.
697 Passing 'ac_cv_prog_cc_stdc=no' to 'configure' now sets ac_cv_prog_cc_c99
698 and ac_cv_prog_cc_c89 to 'no' as well, for backward compatibility with
699 obsolete K&R tests in the Automake test suite.
708 Now more robust with special characters in file names, or when
709 multiple processes create the same directory at the same time.
711 ** Obsolescent macros
712 The documentation now says that the following macros are obsolescent:
713 they test for problems that are so old that they are no longer of
714 practical importance on current systems.
716 AC_C_BACKSLASH_A AC_FUNC_MEMCMP AC_HEADER_DIRENT
717 AC_C_CONST AC_FUNC_SELECT_ARGTYPES AC_HEADER_STAT
718 AC_C_PROTOTYPES AC_FUNC_SETPGRP AC_HEADER_STDC
719 AC_C_STRINGIZE AC_FUNC_SETVBUF_REVERSED AC_HEADER_SYS_WAIT
720 AC_C_VOLATILE AC_FUNC_STAT AC_HEADER_TIME
721 AC_FUNC_CLOSEDIR_VOID AC_FUNC_STRFTIME AC_ISC_POSIX
722 AC_FUNC_GETPGRP AC_FUNC_UTIME_NULL AC_PROG_GCC_TRADITIONAL
723 AC_FUNC_LSTAT AC_FUNC_VPRINTF AC_STRUCT_TM
725 New programs need not use these macros. We have no current plans to
729 For compatibility with future Libtool 2.0, autoreconf will invoke
730 libtoolize with the option `--ltdl' now, if LT_CONFIG_LTDL_DIR is
733 * Major changes in Autoconf 2.59c
735 Released 2006-04-12, by Ralf Wildenhues.
737 ** The configure command now redirects standard input from /dev/null,
738 to help avoid problems with subsidiary commands that might mistakenly
739 read standard input. AS_ORIGINAL_STDIN_FD points to the original
740 standard input before this redirection, if you really want configure to
741 read from standard input.
743 ** Directory variables adjusted to recent changes in the GNU Coding Standards.
744 The following directory variables are new:
746 datarootdir read-only architecture-independent data root [PREFIX/share]
747 localedir locale-specific message catalogs [DATAROOTDIR/locale]
748 docdir documentation root [DATAROOTDIR/doc/PACKAGE]
749 htmldir html documentation [DOCDIR]
750 dvidir dvi documentation [DOCDIR]
751 pdfdir pdf documentation [DOCDIR]
752 psdir ps documentation [DOCDIR]
754 The following variables have new default values:
756 datadir read-only architecture-independent data [DATAROOTDIR]
757 infodir info documentation [DATAROOTDIR/info]
758 mandir man documentation [DATAROOTDIR/man]
760 This means that if you use any of `@datadir@', `@infodir@', or
761 `@mandir@' in a file, you will have to ensure `${datarootdir}' is
762 defined in this file. As a temporary measure, if any of those are
763 found but no mention of `datarootdir', the substitutions will be
764 replaced with values that do not contain `${datarootdir}', and a
765 warning will be issued.
767 ** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
768 a trailing slash. Similar change will be made to ac_top_builddir in a
769 future release; the old style value, which matches (../)*, is (and will
770 continue to be) available as ac_top_build_prefix.
773 New macro to check for support of 'typeof' syntax a la GNU C.
775 ** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
776 New "once-only" variants of commonly-used macros, to make 'configure'
777 smaller and faster in common cases.
780 New macro to check for strtold with C99 semantics.
783 New macro that lets builder disable assertions at 'configure'-time.
786 Now checks for X11/Xlib.h and XrmInitialize (X proper) rather than
787 X11/Intrinsic.h and XtMalloc (Xt).
789 ** AC_PRESERVE_HELP_ORDER
790 New macro that causes `configure' to display help strings for AC_ARG_ENABLE
791 and AC_ARG_WITH arguments in one region, in the order defined. The default
792 behavior is to group options of each classes separately.
794 ** AC_PROG_CC, AC_PROG_CXX
795 No longer automatically arrange to declare the 'exit' function of C,
796 when a C++ compiler is used. Standard Autoconf macros no longer use
797 'exit', so this is no longer an issue for them. If you use C++, and
798 want to call 'exit', you'll have to arrange for its declaration
799 yourself. But we now suggest you return from 'main' instead.
801 ** AC_PROG_CC_C89, AC_PROG_CC_C99
802 New macros for ISO C99 support. AC_PROG_CC_C89 and AC_PROG_CC_C99
803 check for ANSI C89 and ISO C99 support respectively.
806 Has been unobsoleted, and will check if the compiler supports ISO
807 C99, falling back to ANSI C89 if not. ac_cv_prog_cc_stdc is
808 retained for backwards compatibility, assuming the value of
809 ac_cv_prog_cc_c99 or ac_cv_prog_cc_c89 (whichever is valid, in
812 ** AC_STRUCT_DIRENT_D_INO, AC_STRUCT_DIRENT_D_TYPE
813 New macros for checking commonly-used members of struct dirent.
816 The substituted value can now contain newlines.
819 The substitution now occurs only when @variable@ is on a line by itself,
820 optionally surrounded by spaces and tabs. The whole line is replaced.
822 ** AC_TYPE_LONG_DOUBLE, AC_TYPE_LONG_DOUBLE_WIDER
823 New macros to check for long double, and whether it is wider than double.
824 The old macro AC_C_TYPE_LONG_DOUBLE has been marked as obsolete;
825 applications should switch to the new macro.
827 ** AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, AC_TYPE_INT64_T,
828 AC_TYPE_INTMAX_T, AC_TYPE_INTPTR_T, AC_TYPE_LONG_LONG_INT, AC_TYPE_SSIZE_T,
829 AC_TYPE_UINT8_T, AC_TYPE_UINT16_T, AC_TYPE_UINT32_T, AC_TYPE_UINT64_T,
830 AC_TYPE_UINTMAX_T, AC_TYPE_UINTPTR_T, AC_TYPE_UNSIGNED_LONG_LONG_INT
831 New macros to check for C99 and POSIX types.
833 ** AC_USE_SYSTEM_EXTENSIONS
834 New macro to enable extensions to Posix.
837 New macro which is defined to the name of the first declared config header
838 or undefined if no config headers have been declared yet.
841 The macro correctly handles quadrigraphs now.
843 ** AS_BOURNE_COMPATIBLE, AS_SHELL_SANITIZE, AS_CASE
844 These macros are new or published now.
847 New macro for copyright notices in testsuite files.
849 ** ALLOCA, LIBOBJS, LTLIBOBJS
850 Object names added to these variables are now prefixed with `${LIBOBJDIR}',
851 as in `${LIBOBJDIR}alloca.o'. LIBOBJDIR is meant to be defined from
852 `Makefile.in' in case the object files lie in a different directory.
853 The LIBOBJDIR feature is experimental.
856 Supports --no-recursive now.
858 ** New macros to support Erlang/OTP.
859 New macros for configuring paths to Erlang tools and libraries:
860 AC_ERLANG_PATH_ERLC, AC_ERLANG_NEED_ERLC, AC_ERLANG_PATH_ERL,
861 AC_ERLANG_NEED_ERL, AC_ERLANG_CHECK_LIB, AC_ERLANG_SUBST_ROOT_DIR,
862 AC_ERLANG_SUBST_LIB_DIR.
864 New macros for configuring installation of Erlang libraries:
865 AC_ERLANG_SUBST_INSTALL_LIB_DIR, AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR.
867 ** The manual now mentions Gnulib more prominently.
869 ** New macros to support Objective C.
870 AC_PROG_OBJC, AC_PROG_OBJCPP.
872 * Major changes in Autoconf 2.59b
874 Released 2004-08-20, by Paul Eggert.
877 New macro that computes the default alignment of a type.
879 ** AC_CHECK_TOOL, AC_PATH_TOOL, AC_CHECK_TOOLS
880 When cross-compiling, these macros will give a warning if the tool
881 is not prefixed. In the future, unprefixed cross tools will not
882 be detected; please consult the info documentation for information
883 about the reason of this change.
885 ** AC_CHECK_TARGET_TOOL, AC_PATH_TARGET_TOOL, AC_CHECK_TARGET_TOOLS
886 New macros that detect programs whose name is prefixed with the
887 target type, if the build type and target type are different.
889 ** AC_REQUIRE_AUX_FILE
890 New trace macro that declares expected auxiliary files.
893 New macro that tests for a grep program that accepts as a long a line
896 ** AC_PROG_EGREP, AC_PROG_FGREP
897 These macros now require AC_PROG_GREP, and try EGREP="$GREP -E" and
898 FGREP="$GREP -F" respectively if possible, or else run a path search for
899 a program that accepts as long a line as possible.
902 New macro that tests for a sed program that truncates as few characters
905 * Major changes in Autoconf 2.59
907 Released 2003-11-04, by Akim Demaille
909 ** ac_abs_builddir etc.
910 Absolute file names were actually relative in 2.58.
912 * Major changes in Autoconf 2.58
914 Released 2003-11-04, by Akim Demaille
917 core.* files are no longer removed, as they may be valid user files.
919 ** autoreconf and auxiliary directory
920 Autoreconf creates the auxiliary directory if needed. This is
921 especially useful for initial "bootstrapping" of fresh CVS checkouts.
923 ** AC_CONFIG_MACRO_DIR
924 Use this macro to declare the directory for local M4 macros for aclocal.
927 No longer includes twice the same file in LIBOBJS if invoked
930 ** AC_CONFIG_COMMANDS
931 The directory for its first argument is automatically created. For
934 AC_CONFIG_COMMANDS([src/modules.hh], [...])
936 $top_builddir/src/ is created if needed.
938 ** Autotest and local.at
939 The optional file local.at is always included in Autotest test suites.
942 The warnings are always issued, including with cached runs.
943 This became a significant problem since aclocal and automake can
944 run autoconf behind the scene.
946 ** autoheader warnings
947 The warnings of autoheader can be turned off, using --warning.
948 For instance, -Wno-obsolete disables the complaints about acconfig.h
949 and other deprecated constructs.
952 AC_C_RESTRICT, AC_INCLUDES_DEFAULT, AC_LANG_ASSERT, AC_LANG_WERROR,
955 ** AC_DECL_SYS_SIGLIST
959 Now checks that mktime is the inverse of localtime.
961 ** Improve DJGPP portability
962 The Autoconf tools and configure behave better under DJGPP.
964 ** Present But Cannot Be Compiled
965 New FAQ section dedicated to the mystic
967 configure: WARNING: pi.h: present but cannot be compiled
968 configure: WARNING: pi.h: check for missing prerequisite headers?
969 configure: WARNING: pi.h: proceeding with the preprocessor's result
972 ** Concurrent executions of autom4te
973 autom4te now locks its internal files, which enables concurrent
974 executions of autom4te, likely to happen if automake, autoconf,
975 autoheader etc. are run simultaneously.
978 Use of Libtool 1.5 and higher is encouraged. Compatibility with
979 Libtool pre-1.4 is not checked.
982 Testsuites no longer rerun failed tests in verbose mode; instead,
983 failures are logged while the test is run.
985 In addition, expected failures can be marked as such.
987 * Major changes in Autoconf 2.57
989 Released 2002-12-03 by Paul Eggert.
991 Bug fixes for problems with AIX linker, with freestanding C compilers,
992 with GNU M4 limitations, and with obsolete copies of GNU documents.
994 The Free Documentation License has been upgraded from 1.1 to 1.2.
996 * Major changes in Autoconf 2.56
998 Released 2002-11-15 by Akim Demaille.
1000 One packaging problem fixed (config/install-sh was not executable).
1002 * Major changes in Autoconf 2.55
1004 Released 2002-11-14 by Akim Demaille.
1008 Have your configure.ac checked by autoscan ("autoscan").
1009 Try the warning options ("autoreconf -fv -Wall").
1013 - AC_CHECK_HEADER, AC_CHECK_HEADERS
1014 More information on proper use.
1016 - Writing Test Programs
1018 This sections explains how to write good test sources to use with
1019 AC_COMPILE_IFELSE etc. It documents AC_LANG_PROGRAM and so forth.
1021 - AC_FOO_IFELSE vs. AC_TRY_FOO
1023 Explains why Autoconf moves from AC_TRY_COMPILE etc. to
1024 AC_COMPILE_IFELSE and AC_LANG_PROGRAM etc.
1028 - Is more robust to different Gettext installations.
1030 - Produces messages (when --verbose) to be understood by Emacs'
1033 - Supports -W/--warnings.
1036 Once the GNU Build System reinstalled, run `./config.status
1037 --recheck && ./config.status && make' if possible.
1041 - Supports --cache, and --no-cache.
1043 - ~/.autom4te.cfg makes it possible to disable the caching mechanism
1044 (autom4te.cache). See `Customizing autom4te' in the documentation.
1051 Support for the obsoleted options -m, --macrodir, -l, --localdir is
1052 dropped in favor of the safer --include/--prepend-include scheme.
1057 AC_COMPILER_IFELSE, AC_FUNC_MBRTOWC, AC_HEADER_STDBOOL,
1058 AC_LANG_CONFTEST, AC_LANG_SOURCE, AC_LANG_PROGRAM, AC_LANG_CALL,
1059 AC_LANG_FUNC_TRY_LINK, AC_MSG_FAILURE, AC_PREPROC_IFELSE.
1062 Obsoleted macros are kept for Autoconf backward compatibility, but
1063 should be avoided in configure.ac. Running autoupdate is advised.
1064 AC_DECL_SYS_SIGLIST.
1066 - AC_DEFINE/AC_DEFINE_UNQUOTED
1068 We have to stop using the old compatibility scheme --that tried to
1069 avoid useless backslashes-- because Libtool 1.4.3 contains a
1071 AC_DEFINE([error_t], [int],
1072 [Define to a type to use for \`error_t' if it is not
1073 otherwise available.])
1075 We have to quote the single quotes and backslashes with \. The old
1076 compatibility scheme saw that ` was backslashed, and therefore did
1077 not quote the single quote... Failure. Hence, Autoconf 2.54 is not
1078 compatible with Libtool. Autoconf 2.55 is, but in some cases might
1079 produce more \ than wanted.
1081 Please, note that in the future the same problem will happen with
1082 AC_MSG_*: use `autoreconf -f -Wall'.
1086 - Portability of the Autoconf package to Solaris.
1088 - Spurious warnings caused by config.status.
1089 This bug is benign, but painful: on some systems (typically
1090 FreeBSD), warnings such as:
1092 config.status: creating Makefile
1093 mv: Makefile: set owner/group (was: 1357/0): Operation not permitted
1095 could be issued. This is fixed.
1098 Simultaneous executions of config.status are possible again.
1100 - Precious variables accumulation
1102 config.status could stack several copies of the precious variables
1106 ** Plans for later versions
1108 - ./configure <host>
1110 The compatibility hooks with the old scheme will be completely
1111 removed. Please, advice/use `--build', `--host', and `--target'
1114 - AC_CHECK_HEADER, AC_CHECK_HEADERS
1116 The tests will be stricter, please make sure your invocations are
1121 Shell functions will gradually be introduced, probably starting with
1122 Autotest. If you know machines which are in use that you suspect
1123 *not* to support shell functions, please run the test suite of
1124 Autoconf 2.55 on it, and report the results to
1125 bug-autoconf@gnu.org.
1129 Special characters in AC_MSG_* need not be quoted. Currently,
1130 Autoconf has heuristics to decide when a string is escaped, or has
1131 to be escaped. This scheme is fragile, and will be removed; the
1132 only risk is uglified messages. Please, run `autoreconf -f -Wall'
1133 to find occurrences that will be affected.
1135 * Major changes in Autoconf 2.54
1137 Released 2002-09-13 by Akim Demaille.
1141 - autoreconf no longer changes the version of the gettext/po/intl
1142 support files. It now adds the files the correspond to the
1143 AM_GNU_GETTEXT_VERSION declared in configure.ac.
1145 Warning: It now relies on the 'autopoint' program, which is part
1146 of GNU gettext 0.11.4 and newer.
1148 Please note that you need to have a GNU gettext version that
1149 corresponds at least to the AM_GNU_GETTEXT_VERSION declared
1150 in configure.ac. You can upgrade to newer GNU gettext versions,
1151 though, without needing to change configure.ac.
1153 - The -I DIR or --include=DIR option now appends DIR to the include path
1154 instead of prepending; this is for consistency with other GNU tools.
1155 The new -B DIR or --prepend-include=DIR option has the old behavior.
1160 Now handles all the gory details about LIBOBJS and LTLIBOBJS.
1161 Please, remove lines such as
1163 # This is necessary so that .o files in LIBOBJS are also
1164 # built via the ANSI2KNR-filtering rules.
1165 LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
1167 and read the `AC_LIBOBJ vs LIBOBJS' section. Do not define U in
1168 your Makefiles either.
1170 - AC_CONFIG_LINKS now makes copies if it can't make links.
1172 - AC_FUNC_FNMATCH now tests only for POSIX compatibility, reverting to
1173 Autoconf 2.13 behavior. The new macro AC_FUNC_FNMATCH_GNU also
1174 tests for GNU extensions to fnmatch, and replaces fnmatch if needed.
1176 - AC_FUNC_SETVBUF_REVERSED no longer fails when cross-compiling.
1178 - AC_PROG_CC_STDC is integrated into AC_PROG_CC.
1180 - AC_PROG_F77 default search no longer includes cf77 and cfg77.
1184 AC_C_BACKSLASH_A, AC_CONFIG_LIBOBJ_DIR, AC_GNU_SOURCE,
1185 AC_PROG_EGREP, AC_PROG_FGREP, AC_REPLACE_FNMATCH,
1186 AC_FUNC_FNMATCH_GNU, AC_FUNC_REALLOC, AC_TYPE_MBSTATE_T.
1188 - AC_FUNC_GETLOADAVG
1189 looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
1192 Now defines HAVE_MALLOC to 0 if `malloc' does not work, and asks
1193 for an AC_LIBOBJ replacement.
1197 - Spurious complaints from `m4_bmatch' about invalid regular
1198 expressions are suppressed.
1200 - Empty top_builddirs are properly handled.
1202 - AC_CHECK_MEMBER works correctly when the member is an aggregate.
1205 Now colon in the optional path arguments are properly handled.
1207 ** Improved portability
1209 - Both Autoconf the package, and the scripts it produces, should run
1210 more reliably with Zsh. Bear in mind it is the default Bourne shell
1213 - Autoconf and the scripts it produces no longer assume the existence of
1214 the obsolescent commands egrep and fgrep.
1218 - Limitations of Make
1222 The GNATS base moved to
1223 http://bugs.gnu.org/cgi-bin/gnatsweb.pl?database=autoconf
1224 (It is no longer available, though.)
1229 Now contains the list of ouput variables and files (AC_SUBST,
1232 * Major changes in Autoconf 2.53
1234 Released 2002-03-08 by Akim Demaille.
1238 Perl 5.005_03 or later is required: autom4te is written in Perl and is
1239 needed by autoconf. autoheader, autoreconf, ifnames, and autoscan are
1245 Argument requirements, output variables, defined macros.
1246 - M4sugar, M4sh, Autotest
1248 - Double quoting macros
1249 AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
1251 The Autoconf manual is now distributed under the terms of the GNU FDL.
1252 - Section `Hosts and Cross-Compilation'
1253 Explains the rationale for the 2.5x changes in the cross-compilation
1254 chain, and in the relationships between build, host, and target
1256 Emphasizes that `cross-compilation' == `--host is given'.
1257 If you are working on compilers etc., be sure to read this section.
1258 - Section `AC_LIBOBJ vs. LIBOBJS'
1259 Explains why assigning LIBOBJS directly is now an error.
1260 Details how to update the code.
1265 Now used instead of hard coded line numbers.
1266 This eases the comparison of `configure's, and diminishes the
1267 pressure over control version archives.
1268 Automatic replacement for shells that don't support this feature.
1269 - New output variables
1270 @builddir@, @top_builddir@, @abs_srcdir@, @abs_top_srcdir@, @abs_builddir@,
1275 Autoconf and Autotest modes are provided.
1280 New, used by the Autoconf suite to cache and speed up most processing.
1282 Supported by autom4te, autoconf and autoheader.
1284 Replaces --autoconf-dir and --localdir in autoconf, autoheader,
1285 autoupdate, and autoreconf.
1287 No longer passes --cygnus, --foreign, --gnits, --gnu, --include-deps:
1288 automake options are to be given via AUTOMAKE_OPTIONS.
1290 Runs gettextize and libtoolize when appropriate.
1292 --m4dir is no longer supported.
1294 Now runs only in the specified directories, defaulting to `.',
1295 but understands AC_CONFIG_SUBDIRS for dependent directories.
1296 Before, it used to run on all the `configure.ac' found in the
1298 Independent packages are properly updated.
1302 - The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
1304 Under the user pressure, $? is finally available. Probably a mistake.
1305 - AC_F77_LIBRARY_LDFLAGS now supports the HP/UX f90 compiler.
1306 - Precious variables accumulation
1307 config.status could stack several copies of the precious variables
1309 - AC_PATH_PROG and family.
1310 Works properly when given a literal path.
1312 Somewhere since 2.13, the result had been reversed.
1316 - AC_C_BIGENDIAN supports the cross-compiling case.
1317 - AC_C_BIGENDIAN accepts ACTION-IF-TRUE, ACTION-IF-FALSE, and
1318 ACTION-IF-UNKNOWN arguments. All are facultative, and the default
1319 for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
1321 - AC_C_LONG_DOUBLE now succeeds only if `long double' has more range or
1322 precision than `double'.
1327 It now defines the preprocessor symbols PACKAGE_NAME,
1328 PACKAGE_TARNAME, PACKAGE_VERSION, PACKAGE_STRING, and
1332 Admits a fourth optional parameter: the tar name.
1334 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS.
1335 Provide the user with srcdir, ac_srcdir, ac_top_srcdir, ac_builddir,
1336 ac_top_builddir, ac_abs_srcdir, ac_abs_top_srcdir, ac_abs_builddir,
1337 ac_abs_top_builddir.
1339 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS and AC_OUTPUT.
1340 Are much less expensive when using long lists of files.
1343 Works with shell variables, and non alphanumeric names.
1347 - AC_FUNC_STRERROR_R now sets STRERROR_R_CHAR_P, not HAVE_WORKING_STRERROR_R,
1348 because POSIX 1003.1-200x draft 7 says strerror_r returns int, not char *.
1350 - AC_FUNC_STRTOD substitutes POW_LIB.
1355 * Major changes in Autoconf 2.52
1357 Released 2001-07-18 by Akim Demaille.
1362 This feature was present in autoconf 2.50 but was not documented.
1363 For example, `@<:@' is translated to `[' just before output. This
1364 is useful when writing strings that contain unbalanced quotes, or
1365 other hard-to-quote constructs.
1366 - m4_pattern_forbid, m4_pattern_allow
1367 - Tips for upgrading from 2.13.
1368 - Using autoscan to maintain a configure.ac.
1371 - Now include stdint.h.
1372 - sys/types.h and sys/stat.h are guarded.
1373 - strings.h is included if available, and not conflicting with string.h.
1376 - The test suite is more robust and presents less false failures.
1377 - Invocation of GNU M4 now robust to POSIXLY_CORRECT.
1378 - configure accepts --prefix='' again.
1379 - AC_CHECK_LIB works properly when its first argument is not a
1381 - HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
1382 - build_, host_, and target_alias are AC_SUBST as in 2.13.
1383 - AC_ARG_VAR properly propagates precious variables inherited from the
1384 environment to ./config.status.
1385 - Using --program-suffix/--program-prefix is portable.
1386 - Failures to detect the default compiler's output extension are less
1388 - `config.status foo' works properly when `foo' depends on variables
1389 set in an AC_CONFIG_THING INIT-CMD.
1390 - autoheader is more robust to broken input.
1391 - Fixed Fortran name-mangling and link tests on a number of systems,
1392 e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
1395 - AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
1396 specify pre-includes. In this case, the headers are compiled with
1397 cc, not merely preprocessed by cpp. Therefore it is the _usability_
1398 of a header which is checked for, not just its availability.
1399 - AC_ARG_VAR refuses to run configure when precious variables have
1401 - Versions of compilers are dumped in the logs.
1402 - AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
1405 - AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
1406 - AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
1407 - AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
1408 AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
1409 Be sure to read `Upgrading from Version 2.13' to understand why
1410 running `autoupdate' is needed.
1411 - AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
1412 a main-like routine is required/possible when linking C/C++ with
1413 Fortran. Users of e.g. AC_F77_WRAPPERS should be aware of these.
1414 - AC_FUNC_GETPGRG behaves better when cross-compiling.
1416 * Major changes in Autoconf 2.51
1417 There was no release of Autoconf 2.51 since some packagers had used
1418 this version number without permission to ship intermediary versions
1419 of 2.50. The version was skipped to avoid confusion.
1421 * Major changes in Autoconf 2.50
1423 Released 2001-05-21 by Akim Demaille.
1425 ** Lots of bug fixes
1426 There have been far too many to enumerate them here. Check out
1427 ChangeLog if you really want to know more.
1429 ** Improved documentation
1430 In particular, portability issues are better covered.
1433 All the standard GNU Makefile targets are supported. The layout has
1434 changed: m4/ holds the M4 extensions Autoconf needs for its
1435 configuration, doc/ contains the documentation, and tests/ contains
1438 ** Man pages are provided
1439 For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
1440 config.guess, config.sub.
1444 Provides a safe and powerful means to trace the macro uses. This
1445 provide the parsing layer for tools which need to `study'
1449 Specify what category of warnings should be enabled.
1451 - When recursing into subdirectories, try for configure.gnu before
1452 configure to adapt for packages not using autoconf on case-insensitive
1456 More errors are now caught (circular AC_REQUIRE dependencies,
1457 AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
1458 etc.). In addition, their location and call stack are given.
1461 autoupdate is much more powerful, and is able to provide the glue code
1462 which might be needed to move from an old macro to its newer
1465 You are strongly encouraged to use it to modernize both your
1466 `configure.in' and your .m4 extension files.
1469 The internal machinery of autoheader has completely changed. As a
1470 result, using `acconfig.h' should be considered to be obsoleted, and
1471 you are encouraged to get rid of it using the AH macros.
1476 ** Fortran 77 compilers
1477 Globally, the support for Fortran 77 is considerably improved.
1479 Support for automatically determining a Fortran 77 compiler's
1480 name-mangling scheme. New CPP macros F77_FUNC and F77_FUNC_ are
1481 provided to wrap C/C++ identifiers, thus making it easier and more
1482 transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
1483 call C/C++ routines. See the Texinfo documentation for details.
1486 The test suite no longer uses DejaGNU. It should be easy to submit
1487 test cases in this new framework.
1490 - --help, --help=long, -hl
1491 no longer dumps useless items.
1493 lists only specific options.
1494 - --help=recursive, -hr
1495 displays the help of all the embedded packages.
1496 - Remembers environment variables when reconfiguring.
1497 The previous scheme to set envvar before running configure was
1499 what prevented configure from remembering the environment in which
1500 it was run, therefore --recheck was run in an inconsistent
1501 environment. Now, one should run
1503 and then --recheck will work properly. Variables declared with
1504 AC_ARG_VAR are also preserved.
1506 $build defaults to `config.guess`, $host to $build, and then $target
1508 Cross-compilation is a global status of the package, it no longer
1509 depends upon the current language.
1510 Cross compilation is enabled iff the user specified `--host'.
1511 `configure' now fails if it can't run the executables it compiles,
1512 unless cross-compilation is enabled.
1514 The cache file is disabled by default. The new options
1515 `--config-cache', `-C' set the cache to `config.cache'.
1519 Much faster on most architectures.
1520 - concurrent executions
1521 It is safe to use `make -j' with config.status.
1522 - human interface improved
1523 It is possible to invoke
1524 ./config.status foobar
1525 instead of the former form (still valid)
1526 CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
1527 CONFIG_FILES=foobar:foo.in:bar.in \
1529 The same holds for configuration headers and links.
1530 You can instantiate unknown files and headers:
1531 ./config.status --header foo.h:foo.h.in --file bar:baz
1532 - has a useful --help
1533 - accepts special file name "-" for stdin/stdout
1538 Specify additional copyright information.
1541 Now expects the identity of the package as argument.
1545 Most macros, if not all, now strictly follow the `one quotation
1546 level' rule. This results in a more predictable expansion.
1549 A sly bug in the AC_REQUIRE machinery, which could produce incorrect
1550 configure scripts, was fixed by Axel Thimm.
1554 Document and ask for the registration of an envvar.
1557 Specifies the file which `configure' should look for when trying to
1558 find the source tree (used to be handled by AC_INIT).
1560 - AC_CONFIG_COMMANDS
1561 To add new actions to config.status. Should be used instead of
1565 Replaces AC_LINK_FILES.
1567 - AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
1568 AC_CONFIG_LINKS, and AC_CONFIG_FILES
1569 They now obey sh: you should no longer use shell variables as
1570 argument. Instead of
1572 test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
1573 AC_CONFIG_SUBDIRS($my_subdirs)
1577 if test "$package_foo_enabled" = yes; then
1578 AC_CONFIG_SUBDIRS(foo)
1582 To format an Autoconf macro's help string so that it looks pretty
1583 when the user executes `configure --help'.
1586 ** Generic Test Macros
1588 The interface of the AC_CHECK families of macros (decl, header,
1589 type, member, func) is now uniform. They support the same set of
1592 - AC_CHECK_DECL, AC_CHECK_DECLS
1593 To check whether a symbol is declared.
1595 - AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
1596 No longer need a cross-compilation default.
1599 The test it performs is much more robust than previously, and makes
1600 it possible to test builtin types in addition to typedefs.
1601 It is now schizophrenic:
1602 - AC_CHECK_TYPE(TYPE, REPLACEMENT)
1603 remains for backward compatibility, but its use is discouraged.
1604 - AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
1605 behaves exactly like the other AC_CHECK macros.
1608 Checks whether given types are supported by the system.
1610 - AC_CHECK_MEMBER, AC_CHECK_MEMBERS
1611 Check for given members in aggregates (e.g., pw_gecos in struct
1615 Checks if the compiler supports ISO C, included when needs special
1619 Checking whether the preprocessor indicates missing includes by the
1620 error code. stderr is checked by AC_TRY_CPP only as a fallback.
1623 Takes a language as argument and replaces AC_LANG_C,
1624 AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
1626 - AC_LANG_PUSH, AC_LANG_POP
1627 Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
1630 - AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
1631 AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
1632 AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
1636 Sets GETGROUPS_LIBS.
1638 - AC_FUNC_GETLOADAVG
1639 Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
1642 Now integrates `AC_DECL_YYTEXT' which is obsoleted.
1645 Arrange for large-file support.
1647 - AC_EXEEXT, AC_OBJEXT
1648 You are no longer expected to use them: their computation is
1649 performed by default.
1651 ** C++ compatibility
1652 Every macro has been revisited in order to support at best CC=c++.
1654 Major changes in Autoconf 2.14:
1655 There was no release of GNU Autoconf 2.14.
1657 Major changes in Autoconf 2.13:
1659 Released 1999-05-01 by Ben Elliston.
1661 * Support for building on Win32 systems where the only available C or
1662 C++ compiler is the Microsoft Visual C++ command line compiler
1663 (`cl'). Additional support for building on Win32 systems which are
1664 using the Cygwin or Mingw32 environments.
1665 * Support for alternative object file and executable file extensions.
1666 On Win32, for example, these are .obj and .exe. These are discovered
1667 using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
1668 @EXEEXT@ in the output, respectively.
1669 * New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
1670 AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
1671 AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
1672 * AC_DEFINE now has an optional third argument for a description to be
1673 placed in the config header input file (e.g. config.h.in).
1674 * The C++ code fragment compiled for the C++ compiler test had to be
1675 improved to include an explicit return type for main(). This was
1676 causing failures on systems using recent versions of the EGCS C++
1678 * Fixed an important bug in AC_CHECK_TYPE that would cause a configure
1679 script to report that `sometype_t' was present when only `type_t'
1681 * Merge of the FSF version of config.guess and config.sub to modernize
1682 these scripts. Add support for a few new hosts in config.guess.
1683 Incorporate latest versions of install-sh, mkinstalldirs and
1684 texinfo.tex from the FSF.
1685 * autoreconf is capable of running automake if necessary (and
1687 * Support for Fortran 77. See the Texinfo documentation for details.
1688 * Bug fixes and workarounds for quirky bugs in vendor utilities.
1690 Major changes in Autoconf 2.12:
1692 Released 1996-11-26 by David J. MacKenzie
1694 * AC_OUTPUT and AC_CONFIG_HEADER can create output files by
1695 concatenating multiple input files separated by colons, like so:
1696 AC_CONFIG_HEADER(config.h:conf.pre:config.h.in:conf.post)
1697 AC_OUTPUT(Makefile:Makefile.in:Makefile.rules)
1698 The arguments may be shell variables, to compute the lists on the fly.
1699 * AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
1700 * New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
1703 Major changes in Autoconf 2.11:
1705 Released November 18th, 1996, by David J. MacKenzie
1707 * AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
1708 They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
1709 * AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
1710 * AC_CONFIG_HEADER expands shell variables in its argument.
1711 * New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
1712 * The "checking..." messages and the source code for test programs that
1713 fail are saved in config.log.
1714 * Another workaround has been added for seds with small command length limits.
1715 * config.sub and config.guess recognize more system types.
1718 Major changes in Autoconf 2.10:
1720 Released May 7th, 1996, by Roland McGrath
1723 * The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
1724 changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
1726 Major changes in Autoconf 2.9:
1728 Released March 16th, 1996, by Roland McGrath
1732 Major changes in Autoconf 2.8:
1734 Released March 8th, 1996, by Roland McGrath
1738 Major changes in Autoconf 2.7:
1740 Released November 22nd, 1995, by David J. MacKenzie
1744 Major changes in Autoconf 2.6:
1746 Released November 20th, 1995, by David J. MacKenzie
1750 Major changes in Autoconf 2.5:
1752 Released November 17th, 1995, by Roland McGrath
1754 * New configure options --bindir, --libdir, --datadir, etc., with
1755 corresponding output variables.
1756 * New macro: AC_CACHE_CHECK, to make using the cache easier.
1757 * config.log contains the command being run as well as any output from it.
1758 * AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
1759 * AC_PROG_INSTALL doesn't cache a name for install-sh, for sharing caches.
1760 * AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
1761 AC_CHECK_TOOL can search a path other than $PATH.
1762 * AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
1764 Major changes in Autoconf 2.4:
1766 Released June 14th, 1995, by David J. MacKenzie
1768 * Fix a few bugs found by Emacs testers.
1770 Major changes in Autoconf 2.3:
1772 Released March 27th, 1995, by David J. MacKenzie
1774 * Fix the cleanup trap in several ways.
1775 * Handle C compilers that are picky about option placement.
1776 * ifnames gets the version number from the right directory.
1778 Major changes in Autoconf 2.2:
1780 Released March 8th, 1995, by David J. MacKenzie
1782 * The ifnames utility is much faster but requires a "new awk" interpreter.
1783 * AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
1784 library before existing libs, not after, in case it uses them.
1785 * New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
1786 * Lots of bug fixes.
1787 * Many additions to the TODO file :-)
1789 Major changes in Autoconf 2.1:
1791 Released November 4th, 1994, by David J. MacKenzie
1794 * More explanations in the manual.
1795 * Fix a spurious failure in the testsuite.
1796 * Clarify some warning messages.
1797 * autoreconf by default only rebuilds configure and config.h.in files
1798 that are older than any of their particular input files; there is a
1799 --force option to use after installing a new version of Autoconf.
1801 Thanks to everybody who's submitted changes and additions to Autoconf!
1802 I've incorporated many of them, and am still considering others for
1803 future releases -- but I didn't want to postpone this release indefinitely.
1805 Caution: don't indiscriminately rebuild configure scripts with
1806 Autoconf version 2. Some configure.in files need minor adjustments to
1807 work with it; the documentation has a chapter on upgrading. A few
1808 configure.in files, including those for GNU Emacs and the GNU C
1809 Library, need major changes because they relied on undocumented
1810 internals of version 1. Future releases of those packages will have
1811 updated configure.in files.
1813 It's best to use GNU M4 1.3 (or later) with Autoconf version 2.
1814 Autoconf now makes heavy use of M4 diversions, which were implemented
1815 inefficiently in GNU M4 releases before 1.3.
1817 Major changes in Autoconf 2.0:
1819 Released October 26th, 1994, by David J. MacKenzie
1821 ** New copyright terms:
1822 * There are no restrictions on distribution or use of configure scripts.
1825 * Autoconf manual is reorganized to make information easier to find
1826 and has several new indexes.
1827 * INSTALL is reorganized and clearer and is now made from Texinfo source.
1830 * autoscan to generate a preliminary configure.in for a package by
1831 scanning its source code for commonly used nonportable functions,
1832 programs, and header files.
1833 * ifnames to list the symbols used in #if and #ifdef directives in a
1835 * autoupdate to update a configure.in to use the version 2 macro names.
1836 * autoreconf to recursively remake configure and configuration header
1837 files in a source tree.
1839 ** Changed utilities:
1840 * autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
1841 * autoconf and autoheader can look for package-local definition files
1842 in an alternate directory.
1845 * AC_CACHE_VAL to share results of tests between configure runs.
1846 * AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
1847 that macros invoked with AC_REQUIRE don't interrupt other macros.
1848 * AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
1849 support deciding unguessable features based on the host and target types.
1850 * AC_CONFIG_SUBDIRS to recursively configure a source tree.
1851 * AC_ARG_PROGRAM to use the options --program-prefix,
1852 --program-suffix, and --program-transform-name to change the names
1853 of programs being installed.
1854 * AC_PREFIX_DEFAULT to change the default installation prefix.
1855 * AC_TRY_COMPILE to compile a test program without linking it.
1856 * AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
1857 * AC_CHECK_LIB to check for a particular function and library.
1858 * AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
1859 whether or not the test succeeds. They obsolete AC_CHECKING and AC_VERBOSE.
1860 * AC_SUBST_FILE to insert one file into another.
1861 * AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
1862 * AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
1863 * AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
1864 * AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
1867 * Many macros renamed systematically, but old names are accepted for
1868 backward compatibility.
1869 * AC_OUTPUT adds the "automatically generated" comment to
1870 non-Makefiles where it finds @configure_input@ in an input file, to
1871 support files with various comment syntaxes.
1872 * AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
1873 files when they are not enclosed in @ signs.
1874 * AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
1875 override the file name "config.status".
1876 * AC_OUTPUT takes an optional argument for passing variables from
1877 configure to config.status.
1878 * AC_OUTPUT and AC_CONFIG_HEADER allow you to override the input-file names.
1879 * AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
1880 CPPFLAGS, and LDFLAGS from the environment.
1881 * AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
1882 * AC_PROG_INSTALL looks for install-sh or install.sh in the directory
1883 specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
1884 srcdir/../.. by default.
1885 * AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
1886 * AC_DEFINE no longer prints anything, because of the new result reporting
1887 mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
1888 * AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
1889 * AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
1890 --enable- and --with- options.
1891 * AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
1892 execute on success or failure.
1893 * Checking for C functions in C++ works.
1896 * AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
1897 better maintained with them.
1898 * AC_ARG_ARRAY removed because no one was likely using it.
1899 * AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
1900 take arguments, for consistency with all of the other specific checks.
1903 * Comes with config.sub and config.guess, and uses them optionally.
1904 * Uses config.cache to cache test results. An alternate cache file
1905 can be selected with the --cache-file=FILE option.
1906 * Uses optional shell scripts $prefix/share/config.site and
1907 $prefix/etc/config.site to perform site or system specific initializations.
1908 * configure saves compiler output to ./config.log for debugging.
1909 * New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
1910 * acsite.m4 is the new name for the system-wide aclocal.m4.
1911 * Has a DejaGnu test suite.
1913 Major changes in Autoconf 1.11:
1915 * AC_PROG_INSTALL calls install.sh with the -c option.
1916 * AC_SET_MAKE cleans up after itself.
1917 * AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
1918 * AC_OUTPUT prevents shells from looking in PATH for config.status.
1920 Plus a few other bug fixes.
1922 Major changes in Autoconf 1.10:
1924 * autoheader uses config.h.bot if present, analogous to config.h.top.
1925 * AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
1927 * AC_PROG_CXX looks for cxx as a C++ compiler.
1929 Plus several bugs fixed.
1931 Major changes in Autoconf 1.9:
1933 * AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
1934 * AC_SIZEOF_TYPE generates the cpp symbol name automatically,
1935 and autoheader generates entries for those names automatically.
1936 * AC_FIND_X gets the result from xmkmf correctly.
1937 * AC_FIND_X assumes no X if --without-x was given.
1938 * AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
1939 * AC_PROG_INSTALL finds OSF/1 installbsd.
1941 Major changes in Autoconf 1.8:
1944 * New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
1945 AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
1946 for checking both C++ and C features in one configure script.
1947 * New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
1948 * New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
1949 AC_SET_MAKE, AC_ENABLE.
1952 * AC_FIND_X looks for X in more places.
1953 * AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
1954 install.sh is distributed with Autoconf.
1955 * AC_DECLARE_YYTEXT has been removed because it can't work, pending
1956 a rewrite of quoting in AC_DEFINE.
1957 * AC_OUTPUT adds its comments in C format when substituting in C files.
1958 * AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
1960 ** New or changed command line options:
1961 * configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
1962 * configure accepts --without-PACKAGE, which sets withval=no.
1963 * configure accepts --x-includes=DIR and --x-libraries=DIR.
1964 * Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
1965 * configure accepts --help, --version, --silent/--quiet, --no-create options.
1966 * configure accepts and ignores most other Cygnus configure options, and
1967 warns about unknown options.
1968 * config.status accepts --help, --version options.
1970 ** File names and other changes:
1971 * Relative srcdir values are not made absolute.
1972 * The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
1973 * Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
1974 * autoheader optionally copies config.h.top to the beginning of config.h.in.
1975 * The example Makefile dependencies for configure et al. work better.
1976 * Namespace cleanup: all shell variables used internally by Autoconf
1977 have names beginning with `ac_'.
1979 More big improvements are in process for future releases, but have not
1980 yet been (variously) finished, integrated, tested, or documented enough
1983 Major changes in Autoconf 1.7:
1985 * New macro AC_OBSOLETE.
1986 * Bugs in Makefile.in fixed.
1987 * AC_LONG_FILE_NAMES improved.
1989 Major changes in Autoconf 1.6:
1991 * New macro AC_LONG_64_BITS.
1992 * Multiple .h files can be created.
1993 * AC_FIND_X looks for X files directly if it doesn't find xmkmf.
1994 * AC_ALLOCA defines C_ALLOCA if using alloca.c.
1995 * --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
1996 * Unused --no-create option to configure removed.
1997 * autoheader doesn't change the timestamp of its output file if
1998 the file didn't change.
1999 * All macros that look for libraries now use AC_HAVE_LIBRARY.
2000 * config.status checks three optional environment variables to
2001 modify its behavior.
2002 * The usual bug fixes.
2004 Major changes in Autoconf 1.5:
2006 * New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
2007 * autoconf and autoheader scripts have GNU standards conforming
2008 --version and --help options (they print their message and exit).
2011 Major changes in Autoconf 1.4:
2013 * New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
2014 AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
2015 * autoconf and autoheader use the M4 environment variable to determine the
2016 name of the M4 program to use.
2017 * The --macrodir option to autoconf and autoheader specifies the directory
2018 in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
2019 * autoconf and autoheader can take `-' as their file names, which means to
2020 read stdin as input.
2021 * Resulting configure scripts can take a --verbose option which causes them
2022 to print the results of their tests.
2023 * AC_DEFINE quotes its second argument in such a way that spaces, magic
2024 shell characters, etc. will be preserved during various stages of
2025 expansion done by the shell. If you don't want this, use
2026 AC_DEFINE_UNQUOTED instead.
2027 * Much textual processing done with external calls to tr and sed have been
2028 internalized with builtin M4 `patsubst' and `translit' calls.
2029 * AC_OUTPUT doesn't hardwire the file names it outputs. Instead, you can
2030 set the shell variables `gen_files' and `gen_config' to the list of
2031 file names to output.
2032 * AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
2033 "lex.yy" or "lexyy", depending on the system.
2034 * AC_PROGRAMS_CHECK takes an optional third arg. If given, it is used as
2036 * If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
2037 * AC_CONST works much more reliably on more systems.
2040 Major changes in Autoconf 1.3:
2042 configure no longer requires awk for packages that use a config.h.
2043 Support handling --with-PACKAGE options.
2044 New `autoheader' script to create `config.h.in' from `configure.in'.
2045 Ignore troublesome -lucb and -lPW when searching for alloca.
2046 Rename --exec_prefix to --exec-prefix for GNU standards conformance.
2047 Improve detection of STDC library.
2048 Add AC_HAVE_LIBRARY to check for non-default libraries.
2049 Function checking should work with future GNU libc releases.
2051 Major changes in Autoconf 1.2:
2053 The --srcdir option is now usually unnecessary.
2054 Add a file containing sample comments describing CPP macros.
2055 A comment in config.status tells which host it was configured on.
2056 Substituted variable values can now contain commas.
2057 Fix bugs in various feature checks.
2059 Major changes in Autoconf 1.1:
2061 Added AC_STRCOLL macro.
2062 Made AC_GETLOADAVG check for more things.
2063 AC_OUTPUT argument is now optional.
2068 Copyright (C) 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002,
2069 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation,
2072 Copying and distribution of this file, with or without modification,
2073 are permitted in any medium without royalty provided the copyright
2074 notice and this notice are preserved. This file is offered as-is,
2075 without warranty of any kind.