xref: /netbsd-src/external/gpl3/autoconf/dist/NEWS (revision d874e91932377fc40d53f102e48fc3ee6f4fe9de)
1GNU Autoconf NEWS - User visible changes.
2
3* Noteworthy changes in release 2.69 (2012-04-24) [stable]
4
5** Autoconf now requires perl 5.6 or better (but generated configure
6   scripts continue to run without perl).
7
8* Noteworthy changes in release 2.68b (2012-03-01) [beta]
9  Released by Eric Blake, based on git versions 2.68.*.
10
11** Autoconf-generated configure scripts now unconditionally re-execute
12   themselves with $CONFIG_SHELL, if that's set in the environment.
13
14** The texinfo documentation no longer specifies "front-cover" or
15   "back-cover" texts, so that it may now be included in Debian's
16   "main" section.
17
18** Support for the Go programming language has been added.  The new macro
19   AC_LANG_GO sets variables GOC and GOFLAGS.
20
21** AS_LITERAL_IF again treats '=' as a literal.  Regression introduced in
22   2.66.
23
24** The macro AS_EXECUTABLE_P, present since 2.50, is now documented.
25
26** Macros
27
28- AC_PROG_LN_S and AS_LN_S now fall back on 'cp -pR' (not 'cp -p') if 'ln -s'
29  does not work.  This works better for symlinks to directories.
30
31- New macro AC_HEADER_CHECK_STDBOOL.
32
33- New and updated macros for Fortran support:
34
35    AC_FC_CHECK_BOUNDS to enable array bounds checking
36    AC_F77_IMPLICIT_NONE and AC_FC_IMPLICIT_NONE to disable implicit integer
37    AC_FC_MODULE_EXTENSION to compute the Fortran 90 module name extension
38    AC_FC_MODULE_FLAG for the Fortran 90 module search path flag
39    AC_FC_MODULE_OUTPUT_FLAG for the Fortran 90 module output directory flag
40    AC_FC_PP_SRCEXT for preprocessed Fortran source files extensions
41    AC_FC_PP_DEFINE for the Fortran preprocessor define flag
42
43* Noteworthy changes in release 2.68 (2010-09-22) [stable]
44  Released by Eric Blake, based on git versions 2.67.*.
45
46** AC_MSG_ERROR (and AS_ERROR) can once again be followed immediately by
47   `dnl'.  Regression introduced in 2.66.
48
49** AC_INIT again allows URLs with '?' for its BUG-REPORT argument.
50   Regression introduced in 2.66.
51
52** AC_REPLACE_FUNCS again allows a non-literal argument, such as a shell
53   variable that expands to a list of functions to check.  Regression
54   introduced in 2.66.
55
56** AT_BANNER() with empty argument will cause visual separation from previous
57   test category.
58
59** The macros AC_PREPROC_IFELSE, AC_COMPILE_IFELSE, AC_LINK_IFELSE, and
60   AC_RUN_IFELSE now warn if the first argument failed to use
61   AC_LANG_SOURCE or AC_LANG_PROGRAM to generate the conftest file
62   contents.  A new macro AC_LANG_DEFINES_PROVIDED exists if you have
63   a compelling reason why you cannot use AC_LANG_SOURCE but must
64   avoid the warning.
65
66** The macro m4_define_default is now documented.
67
68** Symlinked config.cache files are supported; configure now tries to
69   update non-symlinked cache files atomically, so that concurrent configure
70   runs do not leave behind broken cache files.  It is still unspecified
71   which subset or union of results is cached though.
72
73** Autotest testsuites should not contain long text lines any more, and be
74   portable even when very many test groups are used.
75
76** AT_CHECK semantics with respect to the Autotest variable $at_status and
77   shell execution environment of the arguments are documented now.
78
79** AC_FC_LIBRARY_LDFLAGS now tolerates output from newer gfortran.
80
81** Newly obsolete macros
82   The following macros have been marked obsolete.  New programs
83   should use the corresponding Gnulib modules.  Gnulib not only
84   detects a larger set of portability problems with these functions,
85   but also provides complete workarounds.
86
87     AC_FUNC_ERROR_AT_LINE  AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK
88     AC_FUNC_MKTIME  AC_FUNC_STRTOD
89
90
91* Major changes in Autoconf 2.67 (2010-07-21) [stable]
92  Released by Eric Blake, based on git versions 2.66.*.
93
94** AC_CONFIG_SUBDIRS with more than one subdirectory at a time works again.
95   Regression introduced in 2.66.
96
97** AC_CHECK_SIZEOF of a pointer type works again.  Regression introduced in
98   2.66.
99
100** New macro AC_FC_LINE_LENGTH to accept long Fortran source code lines.
101
102** AC_PREPROC_IFELSE now keeps the preprocessed output in the conftest.i
103   file for inspection by the commands in the ACTION-IF-TRUE argument.
104
105** AC_INIT again allows parentheses and other characters that are literal
106   in single- or double-quoted strings, and in quoted and unquoted
107   here-documents, for its PACKAGE and VERSION arguments.  Regression
108   introduced in 2.66.
109
110** autoreconf passes warning flags to new enough versions of aclocal.
111
112** Running an Autotest testsuite in parallel mode no longer triggers a
113   race condition that could cause the testsuite run to end early,
114   fixing a sporadic failure in autoconf's own testsuite.  Bug present
115   since introduction of parallel tests in 2.63b.
116
117
118* Major changes in Autoconf 2.66 (2010-07-02) [stable]
119  Released by Eric Blake, based on git versions 2.65.*.
120
121** AC_FUNC_MMAP works in C++ mode again.  Regression introduced in 2.65.
122
123** Use of m4_divert without a named diversion now issues a syntax warning,
124   since it is seldom right to change diversions behind autoconf's back.
125
126** The macros AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, and
127   AC_TYPE_INT64_T work again.  Regression introduced in 2.65.
128
129** AC_PROG_INSTALL correctly uses `shtool' again.  Regression introduced
130   in 2.64.
131
132** Autoconf should work on EBCDIC hosts.
133
134** AC_CHECK_DECL and AC_CHECK_DECLS accept optional function argument types
135   for overloaded C++ functions.
136
137** AS_SET_CATFILE accepts nonliterals in its variable name argument now.
138
139** Autotest testsuites accept an option --recheck to rerun tests that
140   failed or passed unexpectedly during the last non-debug testsuite run.
141
142** AC_ARG_ENABLE and AC_ARG_WITH now also accept `+' signs in `--enable-*'
143   and `--with-*' arguments, converting them to underscores for the variable
144   names.
145
146** In configure scripts, loading CONFIG_SITE no longer searches PATH,
147   and problems in loading the configuration site files are diagnosed.
148
149** Autotest testsuites may optionally provide colored test results.
150
151** The previously undocumented Autotest macros AT_ARG_OPTION and
152   AT_ARG_OPTION_ARG have seen bug fixes and are documented now.
153   AT_ARG_OPTION has been changed in that the negative of a long option
154   --OPTION is now --no-OPTION rather than --noOPTION.
155
156** The macro AS_LITERAL_IF is slightly more conservative; text
157   containing shell quotes are no longer treated as literals.
158   Furthermore, a new macro, AS_LITERAL_WORD_IF, adds an additional
159   level of checking that no whitespace occurs in literals.
160
161** The macros AS_TR_SH and AS_TR_CPP no longer expand their results.
162
163** The following macros are now documented:
164   AS_BOX
165
166** New macro AC_FC_FIXEDFORM to accept fixed-form Fortran.
167
168
169* Major changes in Autoconf 2.65 (2009-11-21) [stable]
170  Released by Eric Blake, based on git versions 2.64.*.
171
172** Autoconf is now licensed under the General Public License version 3
173   or later (GPLv3+).  As with earlier versions, the license includes
174   an exception clause so that you may release a configure script
175   generated by autoconf under the license of your own program.
176
177** New macros to support Objective C++.
178   AC_PROG_OBJCXX  AC_PROG_OBJCXXCPP
179
180** The following undocumented autoconf macros, removed in Autoconf 2.64,
181   have been reinstated:
182   AH_CHECK_HEADERS
183
184   These macros are present only for backwards compatibility purposes.
185
186** The macro AC_LANG_COMPILER no longer fails on embedded systems that
187   lack fopen in the C library, such as AVR or RTEMS (regression
188   introduced in 2.64).
189
190** The AC_FC_FREEFORM macro no longer suffers from a whitespace bug that
191   made it fail with some Fortran compilers (regression introduced in
192   2.64).
193
194** The AC_TYPE_UINT64_T and AC_TYPE_INT64_T macros have been fixed to no
195   longer mistakenly select a 32-bit type on some compilers (bug present
196   since macros were introduced in 2.59c).
197
198** The AC_FUNC_MMAP macro has been fixed to be portable to systems like
199   Cygwin (bug present since macro was introduced in 2.0).
200
201** The following documented autotest macros are new:
202   AT_CHECK_EUNIT
203
204** The following m4sugar macros now quote their expansion:
205   m4_toupper  m4_tolower
206
207** The following m4sugar macros are new:
208   m4_escape
209
210** The m4sugar macro m4_text_wrap now copes with embedded quoting without
211   requiring quadrigraphs.  For uses like AC_ARG_VAR([a], [[b c]]),
212   this gives the intuitive behavior of "[b c]" in the output (2.63
213   gave the output of "[b], [c]", and 2.64 encountered a failure).
214
215** The `$tmp' temporary directory used in config.status is documented for
216   public use now.
217
218** config.status now provides a --config option to produce the configuration.
219
220** Many cache variables used by Autoconf's macros are now documented.
221
222** Configure scripts work better on DJGPP by avoiding a bug present in
223   the DJGPP port of bash 2.04 in handling 'return' in a shell
224   function (regression introduced in 2.64).
225
226* Major changes in Autoconf 2.64 (2009-07-26) [stable]
227  Released by Eric Blake, based on git versions 2.63b.*.
228
229** Autoconf now requires GNU M4 1.4.6 or later.  Earlier versions of M4
230   have a bug in regular expression handling that interferes with some
231   of the speedups provided since Autoconf 2.63.  GNU M4 1.4.13 or
232   later is recommended.
233
234** AS_IF and AS_CASE have been taught to avoid syntax errors even when
235   given arguments that expand to just whitespace.
236
237** The following documented autoconf macros are new:
238   AC_ERLANG_SUBST_ERTS_VER
239
240** The autoheader tool now understands m4 macro arguments passed to
241   AC_DEFINE and AC_DEFINE_UNQUOTED.
242
243** Ensure AT_CHECK can support commands that include a # given with
244   proper m4 quoting.  For shell comments, this is a new feature; for
245   non-shell comments, this fixes a regression introduced in 2.63b.
246   Additionally, AT_CHECK correctly supplies shell escapes for
247   metacharacters occurring in m4 macro expansions within the expected
248   stdout and stderr parameters.
249
250** The macro AT_CHECK now understands the concept of hard failure.  If
251   a test exits with an unexpected status 99, cleanup actions for the
252   test are inhibited and the test is treated as a failure regardless
253   of AT_XFAIL_IF.  It also understands the new directives
254   ignore-nolog, stdout-nolog, and stderr-nolog.
255
256** The following documented autotest macros are new:
257   AT_CHECK_UNQUOTED  AT_FAIL_IF  AT_SKIP_IF
258
259** The following documented m4sugar macros are new:
260   m4_argn  m4_copy_force  m4_default_nblank  m4_default_nblank_quoted
261   m4_ifblank  m4_ifnblank  m4_rename_force
262
263** The autoconf testsuite now exercises all Erlang macros.
264
265* Major changes in Autoconf 2.63b (2009-03-31) [beta]
266  Released by Eric Blake, based on git versions 2.63.*.
267
268** The manual is now shipped under the terms of the GNU FDL 1.3.
269
270** AC_REQUIRE now detects the case of an outer macro which first expands
271   then later indirectly requires the same inner macro.  Previously,
272   this case led to silent out-of-order expansion (bug present since
273   2.50); it now issues a syntax warning, and duplicates the expansion
274   of the inner macro to guarantee dependencies have been met.  See
275   the manual for advice on how to refactor macros in order to avoid
276   the bug in earlier autoconf versions and avoid increased script
277   size in the current version.
278
279** AC_DEFUN_ONCE has improved semantics.  Previously, a macro declared
280   with AC_DEFUN_ONCE warned on a second invocation; and out-of-order
281   expansion was still possible.  Now, dependencies are guaranteed,
282   and subsequent invocations are a silent no-op.  This makes
283   AC_DEFUN_ONCE an ideal macro for silencing AC_REQUIRE warnings.
284
285** The following macros are now defined with AC_DEFUN_ONCE.  This means
286   a subtle change in semantics; previously, an AC_DEFUN macro could
287   expand one of these macros multiple times or surround the macro
288   inside shell conditional text to bypass the effects of these
289   macros, but now the macro will expand exactly once, and prior to
290   the start of any enclosing AC_DEFUN macro:
291   AC_CANONICAL_BUILD  AC_CANONICAL_HOST  AC_CANONICAL_TARGET
292   AC_HEADER_ASSERT  AC_PROG_INSTALL  AC_PROG_MKDIR_P
293   AC_USE_SYSTEM_EXTENSIONS
294
295** AC_LANG_ERLANG works once again (regression introduced in 2.61a).
296
297** AC_HEADER_ASSERT is fixed so that './configure --enable-assert' no
298   longer mistakenly disables assertions.
299
300** AC_INIT now takes an optional fifth parameter that can be used to
301   set AC_PACKAGE_URL, a URL for the package's home page; the URL is
302   used in `configure --help' and is also available via AC_DEFINE.
303
304** Autotest testsuites accept an option --jobs[=N] for parallel testing.
305   This feature is still in testing, and may not work on every
306   platform, help in improving it would be appreciated.
307
308** Autotest testsuites do not attempt to write startup error messages
309   to the log file before that is opened (regression introduced in 2.63).
310
311** Configure scripts now use shell functions.  This feature leads to
312   smaller configure files and faster execution.
313
314** Present But Cannot Be Compiled: Autoconf will now proceed with
315   the compiler's result if a header is present but cannot be compiled.
316   The warning is still printed, and you should really fix it by
317   providing a fourth parameter to AC_CHECK_HEADER/AC_CHECK_HEADERS.
318
319** Autoreconf added aclocal to the set of programs affected by the
320   `autoreconf -I dir' option.
321
322** The following documented m4sugar macros are new:
323   m4_chomp  m4_chomp_all  m4_cleardivert  m4_curry  m4_default_quoted
324   m4_esyscmd_s  m4_map_args  m4_map_args_pair  m4_map_args_sep
325   m4_map_args_w  m4_set_map  m4_set_map_sep  m4_stack_foreach
326   m4_stack_foreach_lifo  m4_stack_foreach_sep
327   m4_stack_foreach_sep_lifo
328
329** The following m4sugar macros are documented now, but in some cases
330   with slightly different semantics than what the previous
331   undocumented version had:
332   m4_copy  m4_dumpdefs  m4_rename  m4_version_prereq
333
334** The m4sugar macro m4_expand has been taught to handle unterminated
335   comments and shell case statements.  As a result, it is used
336   internally in more places, such as AC_DEFINE and AT_CHECK.  Most
337   uses of AC_DEFINE and AT_CHECK should not behave any differently;
338   however, it may be necessary to add double-quoting around
339   unbalanced `(' where single-quoting used to be sufficient.
340
341** The following documented m4sh macros are new:
342   AS_INIT_GENERATED  AS_LINENO_PREPARE  AS_ME_PREPARE  AS_SET_STATUS
343   AS_VAR_APPEND  AS_VAR_ARITH  AS_VAR_COPY
344
345** The following m4sh macros are documented now, but in some cases
346   with slightly different semantics than what the previous
347   undocumented version had:
348   AS_ECHO  AS_ECHO_N  AS_ESCAPE  AS_EXIT  AS_LITERAL_IF  AS_UNSET
349   AS_VAR_IF  AS_VAR_POPDEF  AS_VAR_PUSHDEF  AS_VAR_SET  AS_VAR_SET_IF
350   AS_VAR_TEST_SET  AS_VERSION_COMPARE
351
352** The m4sh macros AS_IF and AS_CASE can now be used in shell lists.
353   The responsibility for supplying a trailing newline now belongs to
354   the call site, but since most users did not add dnl, this generally
355   results in fewer empty lines in configure.
356
357
358* Major changes in Autoconf 2.63 (2008-09-09) [stable]
359  Released by Eric Blake, based on git versions 2.62.*.
360
361** AC_C_BIGENDIAN does not mistakenly report "universal" for some
362   bigendian hosts, a regression introduced with universal binary
363   support in 2.62.
364
365** AC_PATH_X now includes /lib64 and /usr/lib64 in its list of default
366   library directories.
367
368** AC_USE_SYSTEM_EXTENSIONS no longer conflicts with an external
369   AC_DEFINE([__EXTENSIONS__]).  This fixes a regression introduced in
370   2.62 when using macros such as AC_AIX that were made obsolete in
371   favor of the more portable AC_USE_SYSTEM_EXTENSIONS.
372
373** AC_CHECK_TARGET_TOOLS is usable in the non-cross-compile case.
374
375** Newly obsolete macros
376   The following macro has been marked obsolete, since current porting
377   targets can safely assume C89 semantics that signal handlers return
378   void.  We have no current plans to remove the macro.
379
380     AC_TYPE_SIGNAL
381
382** The macros m4_map and m4_map_sep now ignore any list elements
383   consisting of just empty quotes, and m4_map_sep now expands its
384   separator.  This fixes a regression in 2.62 when these macros were
385   first documented, for the sake of clients expecting the semantics
386   that these macros had prior to that time.  The new macros m4_mapall
387   and m4_mapall_sep, along with extra quoting of the separator, can
388   be used to get the semantics that m4_map_sep had in 2.62.
389
390** Clients of m4_expand, such as AS_HELP_STRING and AT_SETUP, can now
391   handle properly quoted but otherwise unbalanced parentheses (for
392   some macros, this fixes a regression in 2.62).
393
394** Two new quadrigraphs have been introduced: @{:@ for (, and @:}@ for ),
395   allowing the output of unbalanced parentheses in more contexts.
396
397** The following m4sugar macros are new:
398   m4_cleardivert  m4_joinall  m4_mapall  m4_mapall_sep  m4_reverse
399   m4_set_add  m4_set_add_all  m4_set_contains  m4_set_contents
400   m4_set_delete  m4_set_difference  m4_set_dump  m4_set_empty
401   m4_set_foreach  m4_set_intersection  m4_set_list  m4_set_listc
402   m4_set_remove  m4_set_size  m4_set_union
403
404** The following m4sugar macros now accept multiple arguments, as is the
405   case with underlying m4:
406   m4_defn  m4_popdef  m4_undefine
407
408** The following m4sugar macros now guarantee linear scaling; they
409   previously had linear scaling with m4 1.6 but quadratic scaling
410   when using m4 1.4.x.  All macros built on top of these also gain
411   the scaling improvements.
412   m4_bmatch  m4_bpatsubsts  m4_case  m4_cond  m4_do  m4_dquote_elt
413   m4_foreach  m4_join  m4_list_cmp  m4_map  m4_map_sep  m4_max
414   m4_min  m4_shiftn
415
416** AT_KEYWORDS once again performs expansion on its argument, such that
417   AT_KEYWORDS([m4_if([$1], [], [default])]) no longer complains about
418   the possibly unexpanded m4_if [regression introduced in 2.62].
419
420** Config header templates `#undef UNDEFINED /* comment */' do not lead to
421   nested comments any more; regression introduced in 2.62.
422
423
424* Major changes in Autoconf 2.62 (2008-04-05) [stable]
425  Released by Eric Blake, based on git versions 2.61a.*.
426
427** Many optimizations have been applied to make overall execution faster.
428
429** Autotest now makes use of shell functions.
430
431** config.status now uses awk instead of sed also for config headers.
432
433   - As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
434     values, i.e., backslash-newline combinations are handled correctly.
435     Further, for config headers, the total size of values is not limited by
436     the POSIX length limit of text lines any more, only each single line.
437
438** New config variable `top_build_prefix'.
439
440** New Autoconf macros:
441   AC_AUTOCONF_VERSION  AC_OPENMP  AC_PATH_PROGS_FEATURE_CHECK
442
443** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.
444
445** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
446   like '__restrict' if the variant spelling is available, as this is
447   more likely to work when mixing C and C++ code.
448
449** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
450   be a string of tokens such that "T y;" is a valid member declaration
451   in a struct.
452
453** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
454   is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.
455
456** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
457   they did not work for function types.  In C++, they now work on any
458   type-id that can be the operand of sizeof; this is similar to C,
459   except it excludes anonymous struct and union types.  Formerly,
460   some (but not all) C++ types involving anonymous struct and union
461   were accepted, though this was not documented.
462
463** AC_CONFIG_LINKS now prefers to link against files in the build tree
464   if found, and it works to link against a file of the same name in
465   the source tree, even if both trees coincide.
466
467** AC_INIT no longer alters $@; regression introduced in 2.60.
468
469** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.
470
471** AS_HELP_STRING no longer underquotes its first argument; it also handles
472   the case where the first argument contains single-quoted commas.
473   For example, "AS_HELP_STRING([-a, [--arg[=foo]]], [bar])" produces:
474     "  -a, --arg[=foo]         bar"
475   Additionally, the macro now takes two additional arguments,
476   indent-column and wrap-column; these should not normally be needed,
477   but can be used to fine-tune how the output text is wrapped.
478
479** AC_PROG_INSTALL now requires an install program that can install multiple
480   files into a target directory.
481
482** The command 'autoconf -' now correctly processes a file from stdin.
483
484** 'autoreconf -m' now honors $MAKE.
485
486** For all of the directory arguments for 'configure', such as '--prefix'
487   or '--bindir', trailing slashes are stripped.  As an example, if
488   tab completion in the user's shell appends trailing slashes, the
489   command './configure --prefix=/usr/' will still result in an
490   expanded libdir value of /usr/lib, not /usr//lib.
491
492** `configure --help=recursive' now works in read-only trees and from
493   unconfigured build trees.
494
495** If precious variables differ only in whitespace, then the cache consistency
496   check warns instead of fails, and reuses the old value.
497
498** AT_BANNER is now documented.
499
500** AT_SETUP now handles macro expansions properly when calculating line
501   length.
502
503** Autotest now determines $srcdir correctly.
504
505** Testsuites built by autotest now accept a -C/--directory=DIR option
506   to adjust the working directory prior to creating files.
507
508** Autoconf now requires GNU M4 1.4.5 or later.  Earlier versions of M4 have
509   a bug in macro tracing that interferes with the interaction between
510   Autoconf and Automake.  GNU M4 1.4.11 or later is recommended.  The
511   configure search for a working M4 is improved.
512
513** For portability with the eventual M4 2.0, macros should no longer use
514   anything larger than $9 to refer to arguments.
515
516** Documentation for m4sugar is improved.
517
518   - The following macros were previously available as undocumented
519     interfaces; the macros are now documented as stable interfaces.
520
521     __oline__  m4_assert  m4_bmatch  m4_bpatsubsts  m4_car  m4_case
522     m4_cdr  m4_default  m4_divert_once  m4_divert_pop  m4_divert_push
523     m4_divert_text  m4_do  m4_errprintn  m4_fatal  m4_flatten
524     m4_ifndef  m4_ifset  m4_ifval  m4_ifvaln  m4_location
525     m4_n  m4_shiftn  m4_strip  m4_warn
526
527   - The following macros were previously available as undocumented
528     interfaces, but had bug fixes or semantic changes as part of this
529     release.  Packages that relied on the undocumented behavior
530     should be analyzed to make sure they will still work with the
531     new documented behavior.
532
533     m4_cmp  m4_list_cmp  m4_join  m4_map  m4_map_sep  m4_sign
534     m4_text_box  m4_text_wrap  m4_version_compare
535
536   - The m4_wrap macro used to have unspecified order, but now
537     guarantees FIFO order.  m4_wrap_lifo was added to guarantee LIFO
538     order.
539
540   - Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
541     should consider using the new AC_AUTOCONF_VERSION instead.
542
543   - m4sugar macros that are not documented in the manual are still
544     deemed experimental, and should not be used outside of Autoconf.
545
546** The m4sugar macros m4_append and m4_append_uniq, first documented in
547   2.60, have been fixed to treat both the string and the separator
548   arguments consistently with regards to quoting.  Prior to this fix,
549   m4_append_uniq could mistakenly duplicate entries if the expansion
550   of the separator resulted in a different string (for example, if it
551   contained quotes, a comma, or a macro name).  However, it means
552   that programs previously using
553     m4_append([name], [string], [[, ]])
554   are now using a four-character separator instead of the intended
555   comma and space.  If you need portability to earlier versions of
556   Autoconf, you can insert the following snippet after AC_INIT but
557   before any other macro expansions, to enforce the new semantics:
558     m4_pushdef([m4_append], [m4_define([$1],
559	   m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
560   Additionally, m4_append_uniq now takes optional parameters that can
561   be used to take action depending on whether anything was appended,
562   and warns if a non-empty separator occurs within the string being
563   appended, since that can lead to duplicates.
564
565** The following m4sugar macros are new:
566   m4_append_uniq_w  m4_apply  m4_combine  m4_cond  m4_count
567   m4_dquote_elt  m4_echo  m4_expand  m4_ignore  m4_make_list  m4_max
568   m4_min  m4_newline  m4_shift2  m4_shift3  m4_unquote  m4_wrap_lifo
569
570** Warnings are now generated by default when an installer invokes
571   'configure' with an unknown --enable-* or --with-* option.
572   These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
573   macro, or by invoking 'configure' with --disable-option-checking.
574
575** Existing obsolete macros
576   The documentation for the following macros is adjusted to make it
577   more clear that they have previously been marked obsolete, as their
578   functionality can be accomplished by other macros.  We have no
579   current plans to remove them from Autoconf.
580
581     AC_ENABLE  AC_STRUCT_ST_BLKSIZE  AC_STRUCT_ST_RDEV  AC_WITH
582
583** Newly obsolete macros
584   The following macros have been marked obsolete, as they only
585   perform a subset of AC_USE_SYSTEM_EXTENSIONS.  We have no current
586   plans to remove them.
587
588     AC_AIX  AC_GNU_SOURCE  AC_ISC_POSIX  AC_MINIX
589
590** AC_C_LONG_DOUBLE is obsolescent.
591   The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
592   tests for problems that are so old that it is no longer of
593   practical importance on current systems.  New programs need not use
594   AC_C_LONG_DOUBLE.  We have no current plans to remove it.
595
596** AC_DIAGNOSE, AC_WARNING, and AC_FATAL are obsolescent.
597   The documentation now favors the use of M4sugar macros m4_warn and
598   m4_fatal, since the naming makes it more obvious that the
599   diagnostics are associated with M4 expansion (ie. when running
600   `autoconf'), and offers less confusion with the AC_MSG_ERROR,
601   AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
602   when running `configure'.  We have no current plans to remove these
603   macros.
604
605
606* Major changes in Autoconf 2.61a (2006-12-11)
607
608** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
609   on many platforms.  This has been fixed.
610
611** AC_FUNC_SETVBUF_REVERSED is now obsolete.  It is still defined for backward
612   compatibility but it does nothing.  The macro was already
613   obsolescent, as the last systems to have the problem were those
614   based on SVR2, which became obsolete in 1987.  The macro had bugs
615   on some modern systems and could no longer be maintained reliably
616   due to lack of ancient systems to test it on.
617
618** config.status now uses awk instead of sed for most substitutions, for speed.
619
620   - As a side effect multi-line values of substituted variables no
621     longer have a small limit in total size, though for portability
622     each line should not exceed the POSIX length limit for text lines.
623
624   - It is now documented that Makefile.in should not contain
625     overlapping variable occurrences, e.g., @VAR1@VAR2@.
626     Autoconf's behavior was always iffy in such cases, and the
627     awk implementation has changed the behavior.
628
629** Many uses of 'echo' have been rewritten so that Autoconf-generated
630   scripts have fewer problems with strings or file names containing
631   embedded special characters such as backslash or leading "-".  This
632   was implemented by using `printf '%s\n' "$foo"' instead of `echo
633   "$foo"' when printf works.  Due to the implementation technique
634   used, Autoconf-generated scripts now run considerably more slowly
635   on ancient implementations lacking printf.  However, this should
636   not be a problem, since Autoconf-generated scripts in practice
637   invariably find a more-modern shell these days.
638
639
640* Major changes in Autoconf 2.61 (2006-11-17)
641
642** New macros AC_C_FLEXIBLE_ARRAY_MEMBER, AC_C_VARARRAYS.
643
644** AC_ARG_ENABLE and AC_ARG_WITH now allow '.' in feature and package names.
645
646
647* Major changes in Autoconf 2.60b (2006-10-22)
648
649** BIN_SH
650  Autoconf-generated shell scripts no longer export BIN_SH, due to
651  configuration hassles with this.  Installers who need BIN_SH in
652  their environment should set it before invoking 'configure' and
653  'make'.  As far as we know, this affects only Unixware installations.
654
655** Obsolescent macros
656  The documentation now says that the following macros are obsolescent,
657  as they are superseded by Gnulib:
658
659    AC_FUNC_FNMATCH  AC_FUNC_FNMATCH_GNU  AC_FUNC_GETLOADVG  AC_REPLACE_FNMATCH
660
661  New programs should use the Gnulib counterparts of these macros.
662  We have no current plans to remove them from Autoconf.
663
664** AC_COMPUTE_INT no longer caches or reports results.
665
666** AC_CHECK_DECL now also works with aggregate objects.
667
668** AC_USE_SYSTEM_EXTENSIONS now defines _TANDEM_SOURCE for NonStop platforms.
669
670** GNU M4 1.4.7 or later is now recommended.
671
672** m4_mkstemp
673  New M4sugar macro, which is more secure than the POSIX M4 maketemp.
674
675** m4_maketemp
676  Now an alias for m4_mkstemp.
677
678* Major changes in Autoconf 2.60a (2006-08-25)
679
680** GNU M4 1.4.6 or later is now recommended.
681
682** The check for C99 now tests for varargs macros, as documented.
683  It also tests that the preprocessor supports 64-bit integers.
684
685** Autoconf now uses constructs like "#ifdef HAVE_STDLIB_H" rather than
686  "#if HAVE_STDLIB_H", so that it now works with "gcc -Wundef -Werror".
687
688** The functionality of the undocumented _AC_COMPUTE_INT is now provided
689  by a public and documented macro, AC_COMPUTE_INT.  The parameters to the
690  two macros are different, so autoupdate will not change the old private name
691  to the new one.  _AC_COMPUTE_INT may be removed in a future release.
692
693** AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT now require
694   that long long types be at least 64 bits wide, as C99 and tradition
695   requires.  Formerly, they accepted implementations of any width.
696
697
698* Major changes in Autoconf 2.60
699
700  Released 2006-06-23, by Ralf Wildenhues.
701
702** Autoconf no longer depends on whether m4wrap is FIFO (as Posix requires)
703  or LIFO (as in GNU M4 1.4.x).  GNU M4 2.0 is expected to conform to Posix
704  here, so m4wrap/m4_wrap users should no longer depend on LIFO behavior.
705
706** Provide a way to turn off warnings about the changed directory variables.
707
708* Major changes in Autoconf 2.59d
709
710  Released 2006-06-05, by Ralf Wildenhues.
711
712** GNU make now recommended for VPATH builds
713  INSTALL now suggests VPATH builds (e.g., "sh ../srcdir/configure")
714  only if you use GNU make.  In practice, other 'make' implementations
715  have too many subtle incompatibilities in their support for VPATH.
716  Many packages (including Autoconf itself) are portable to other
717  'make' implementations, but some packages are not, and recommending
718  GNU make keeps the installation instructions simpler.
719
720** Even more safety checks for the new Directory variables:
721  Warn about suspicious `${datarootdir}' found in config files output.
722
723** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
724  These never-documented macros and variables have been marked with
725  comments saying that they may be removed in a future release,
726  because their use can lead to unintended code being executed.
727  If you need functionality that only these macros or variables
728  currently supply, please write bug-autoconf@gnu.org.
729
730** AC_SUBST, AC_DEFINE
731  Literal arguments to these are passed to m4_pattern_allow now.
732
733** AC_PROG_CC_STDC
734  Passing 'ac_cv_prog_cc_stdc=no' to 'configure' now sets ac_cv_prog_cc_c99
735  and ac_cv_prog_cc_c89 to 'no' as well, for backward compatibility with
736  obsolete K&R tests in the Automake test suite.
737
738** AC_PROG_CXX_C_O
739  New macro.
740
741** AC_PROG_MKDIR_P
742  New macro.
743
744** AS_MKDIR_P
745  Now more robust with special characters in file names, or when
746  multiple processes create the same directory at the same time.
747
748** Obsolescent macros
749  The documentation now says that the following macros are obsolescent:
750  they test for problems that are so old that they are no longer of
751  practical importance on current systems.
752
753    AC_C_BACKSLASH_A       AC_FUNC_MEMCMP            AC_HEADER_DIRENT
754    AC_C_CONST             AC_FUNC_SELECT_ARGTYPES   AC_HEADER_STAT
755    AC_C_PROTOTYPES        AC_FUNC_SETPGRP           AC_HEADER_STDC
756    AC_C_STRINGIZE         AC_FUNC_SETVBUF_REVERSED  AC_HEADER_SYS_WAIT
757    AC_C_VOLATILE          AC_FUNC_STAT              AC_HEADER_TIME
758    AC_FUNC_CLOSEDIR_VOID  AC_FUNC_STRFTIME          AC_ISC_POSIX
759    AC_FUNC_GETPGRP        AC_FUNC_UTIME_NULL        AC_PROG_GCC_TRADITIONAL
760    AC_FUNC_LSTAT          AC_FUNC_VPRINTF           AC_STRUCT_TM
761
762  New programs need not use these macros.  We have no current plans to
763  remove them.
764
765** autoreconf
766  For compatibility with future Libtool 2.0, autoreconf will invoke
767  libtoolize with the option `--ltdl' now, if LT_CONFIG_LTDL_DIR is
768  used.
769
770* Major changes in Autoconf 2.59c
771
772  Released 2006-04-12, by Ralf Wildenhues.
773
774** The configure command now redirects standard input from /dev/null,
775  to help avoid problems with subsidiary commands that might mistakenly
776  read standard input.  AS_ORIGINAL_STDIN_FD points to the original
777  standard input before this redirection, if you really want configure to
778  read from standard input.
779
780** Directory variables adjusted to recent changes in the GNU Coding Standards.
781  The following directory variables are new:
782
783    datarootdir   read-only architecture-independent data root [PREFIX/share]
784    localedir     locale-specific message catalogs [DATAROOTDIR/locale]
785    docdir        documentation root [DATAROOTDIR/doc/PACKAGE]
786    htmldir       html documentation [DOCDIR]
787    dvidir        dvi documentation [DOCDIR]
788    pdfdir        pdf documentation [DOCDIR]
789    psdir         ps documentation [DOCDIR]
790
791  The following variables have new default values:
792
793    datadir       read-only architecture-independent data [DATAROOTDIR]
794    infodir       info documentation [DATAROOTDIR/info]
795    mandir        man documentation [DATAROOTDIR/man]
796
797  This means that if you use any of `@datadir@', `@infodir@', or
798  `@mandir@' in a file, you will have to ensure `${datarootdir}' is
799  defined in this file.  As a temporary measure, if any of those are
800  found but no mention of `datarootdir', the substitutions will be
801  replaced with values that do not contain `${datarootdir}', and a
802  warning will be issued.
803
804** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
805  a trailing slash.  Similar change will be made to ac_top_builddir in a
806  future release; the old style value, which matches (../)*, is (and will
807  continue to be) available as ac_top_build_prefix.
808
809** AC_C_TYPEOF
810  New macro to check for support of 'typeof' syntax a la GNU C.
811
812** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
813  New "once-only" variants of commonly-used macros, to make 'configure'
814  smaller and faster in common cases.
815
816** AC_FUNC_STRTOLD
817  New macro to check for strtold with C99 semantics.
818
819** AC_HEADER_ASSERT
820  New macro that lets builder disable assertions at 'configure'-time.
821
822** AC_PATH_X
823  Now checks for X11/Xlib.h and XrmInitialize (X proper) rather than
824  X11/Intrinsic.h and XtMalloc (Xt).
825
826** AC_PRESERVE_HELP_ORDER
827  New macro that causes `configure' to display help strings for AC_ARG_ENABLE
828  and AC_ARG_WITH arguments in one region, in the order defined.  The default
829  behavior is to group options of each classes separately.
830
831** AC_PROG_CC, AC_PROG_CXX
832  No longer automatically arrange to declare the 'exit' function of C,
833  when a C++ compiler is used.  Standard Autoconf macros no longer use
834  'exit', so this is no longer an issue for them.  If you use C++, and
835  want to call 'exit', you'll have to arrange for its declaration
836  yourself.  But we now suggest you return from 'main' instead.
837
838** AC_PROG_CC_C89, AC_PROG_CC_C99
839  New macros for ISO C99 support.  AC_PROG_CC_C89 and AC_PROG_CC_C99
840  check for ANSI C89 and ISO C99 support respectively.
841
842** AC_PROG_CC_STDC
843  Has been unobsoleted, and will check if the compiler supports ISO
844  C99, falling back to ANSI C89 if not.  ac_cv_prog_cc_stdc is
845  retained for backwards compatibility, assuming the value of
846  ac_cv_prog_cc_c99 or ac_cv_prog_cc_c89 (whichever is valid, in
847  that order).
848
849** AC_STRUCT_DIRENT_D_INO, AC_STRUCT_DIRENT_D_TYPE
850  New macros for checking commonly-used members of struct dirent.
851
852** AC_SUBST
853  The substituted value can now contain newlines.
854
855** AC_SUBST_FILE
856  The substitution now occurs only when @variable@ is on a line by itself,
857  optionally surrounded by spaces and tabs.  The whole line is replaced.
858
859** AC_TYPE_LONG_DOUBLE, AC_TYPE_LONG_DOUBLE_WIDER
860  New macros to check for long double, and whether it is wider than double.
861  The old macro AC_C_TYPE_LONG_DOUBLE has been marked as obsolete;
862  applications should switch to the new macro.
863
864** AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, AC_TYPE_INT64_T,
865   AC_TYPE_INTMAX_T, AC_TYPE_INTPTR_T, AC_TYPE_LONG_LONG_INT, AC_TYPE_SSIZE_T,
866   AC_TYPE_UINT8_T, AC_TYPE_UINT16_T, AC_TYPE_UINT32_T, AC_TYPE_UINT64_T,
867   AC_TYPE_UINTMAX_T, AC_TYPE_UINTPTR_T, AC_TYPE_UNSIGNED_LONG_LONG_INT
868  New macros to check for C99 and POSIX types.
869
870** AC_USE_SYSTEM_EXTENSIONS
871  New macro to enable extensions to Posix.
872
873** AH_HEADER
874  New macro which is defined to the name of the first declared config header
875  or undefined if no config headers have been declared yet.
876
877** AS_HELP_STRING
878  The macro correctly handles quadrigraphs now.
879
880** AS_BOURNE_COMPATIBLE, AS_SHELL_SANITIZE, AS_CASE
881  These macros are new or published now.
882
883** AT_COPYRIGHT
884  New macro for copyright notices in testsuite files.
885
886** ALLOCA, LIBOBJS, LTLIBOBJS
887  Object names added to these variables are now prefixed with `${LIBOBJDIR}',
888  as in `${LIBOBJDIR}alloca.o'.  LIBOBJDIR is meant to be defined from
889  `Makefile.in' in case the object files lie in a different directory.
890  The LIBOBJDIR feature is experimental.
891
892** autoreconf
893  Supports --no-recursive now.
894
895** New macros to support Erlang/OTP.
896  New macros for configuring paths to Erlang tools and libraries:
897  AC_ERLANG_PATH_ERLC, AC_ERLANG_NEED_ERLC, AC_ERLANG_PATH_ERL,
898  AC_ERLANG_NEED_ERL, AC_ERLANG_CHECK_LIB, AC_ERLANG_SUBST_ROOT_DIR,
899  AC_ERLANG_SUBST_LIB_DIR.
900
901  New macros for configuring installation of Erlang libraries:
902  AC_ERLANG_SUBST_INSTALL_LIB_DIR, AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR.
903
904** The manual now mentions Gnulib more prominently.
905
906** New macros to support Objective C.
907  AC_PROG_OBJC, AC_PROG_OBJCPP.
908
909* Major changes in Autoconf 2.59b
910
911  Released 2004-08-20, by Paul Eggert.
912
913** AC_CHECK_ALIGNOF
914  New macro that computes the default alignment of a type.
915
916** AC_CHECK_TOOL, AC_PATH_TOOL, AC_CHECK_TOOLS
917  When cross-compiling, these macros will give a warning if the tool
918  is not prefixed.  In the future, unprefixed cross tools will not
919  be detected; please consult the info documentation for information
920  about the reason of this change.
921
922** AC_CHECK_TARGET_TOOL, AC_PATH_TARGET_TOOL, AC_CHECK_TARGET_TOOLS
923  New macros that detect programs whose name is prefixed with the
924  target type, if the build type and target type are different.
925
926** AC_REQUIRE_AUX_FILE
927  New trace macro that declares expected auxiliary files.
928
929** AC_PROG_GREP
930  New macro that tests for a grep program that accepts as a long a line
931  as possible.
932
933** AC_PROG_EGREP, AC_PROG_FGREP
934  These macros now require AC_PROG_GREP, and try EGREP="$GREP -E" and
935  FGREP="$GREP -F" respectively if possible, or else run a path search for
936  a program that accepts as long a line as possible.
937
938** AC_PROG_SED
939  New macro that tests for a sed program that truncates as few characters
940  as possible.
941
942* Major changes in Autoconf 2.59
943
944  Released 2003-11-04, by Akim Demaille
945
946** ac_abs_builddir etc.
947  Absolute file names were actually relative in 2.58.
948
949* Major changes in Autoconf 2.58
950
951  Released 2003-11-04, by Akim Demaille
952
953** core.*
954  core.* files are no longer removed, as they may be valid user files.
955
956** autoreconf and auxiliary directory
957  Autoreconf creates the auxiliary directory if needed.  This is
958  especially useful for initial "bootstrapping" of fresh CVS checkouts.
959
960** AC_CONFIG_MACRO_DIR
961  Use this macro to declare the directory for local M4 macros for aclocal.
962
963** AC_LIBOBJS
964  No longer includes twice the same file in LIBOBJS if invoked
965  multiple times.
966
967** AC_CONFIG_COMMANDS
968  The directory for its first argument is automatically created.  For
969  instance, with
970
971      AC_CONFIG_COMMANDS([src/modules.hh], [...])
972
973  $top_builddir/src/ is created if needed.
974
975** Autotest and local.at
976  The optional file local.at is always included in Autotest test suites.
977
978** Warnings
979  The warnings are always issued, including with cached runs.
980  This became a significant problem since aclocal and automake can
981  run autoconf behind the scene.
982
983** autoheader warnings
984  The warnings of autoheader can be turned off, using --warning.
985  For instance, -Wno-obsolete disables the complaints about acconfig.h
986  and other deprecated constructs.
987
988** New macros
989  AC_C_RESTRICT, AC_INCLUDES_DEFAULT, AC_LANG_ASSERT, AC_LANG_WERROR,
990  AS_SET_CATFILE.
991
992** AC_DECL_SYS_SIGLIST
993  Works again.
994
995** AC_FUNC_MKTIME
996  Now checks that mktime is the inverse of localtime.
997
998** Improve DJGPP portability
999  The Autoconf tools and configure behave better under DJGPP.
1000
1001** Present But Cannot Be Compiled
1002  New FAQ section dedicated to the mystic
1003
1004    configure: WARNING: pi.h: present but cannot be compiled
1005    configure: WARNING: pi.h: check for missing prerequisite headers?
1006    configure: WARNING: pi.h: proceeding with the preprocessor's result
1007      messages.
1008
1009** Concurrent executions of autom4te
1010  autom4te now locks its internal files, which enables concurrent
1011  executions of autom4te, likely to happen if automake, autoconf,
1012  autoheader etc. are run simultaneously.
1013
1014** Libtool
1015  Use of Libtool 1.5 and higher is encouraged.  Compatibility with
1016  Libtool pre-1.4 is not checked.
1017
1018** Autotest
1019  Testsuites no longer rerun failed tests in verbose mode; instead,
1020  failures are logged while the test is run.
1021
1022  In addition, expected failures can be marked as such.
1023
1024* Major changes in Autoconf 2.57
1025
1026  Released 2002-12-03 by Paul Eggert.
1027
1028Bug fixes for problems with AIX linker, with freestanding C compilers,
1029with GNU M4 limitations, and with obsolete copies of GNU documents.
1030
1031The Free Documentation License has been upgraded from 1.1 to 1.2.
1032
1033* Major changes in Autoconf 2.56
1034
1035  Released 2002-11-15 by Akim Demaille.
1036
1037One packaging problem fixed (config/install-sh was not executable).
1038
1039* Major changes in Autoconf 2.55
1040
1041  Released 2002-11-14 by Akim Demaille.
1042
1043Release tips:
1044
1045	   Have your configure.ac checked by autoscan ("autoscan").
1046	     Try the warning options ("autoreconf -fv -Wall").
1047
1048** Documentation
1049
1050- AC_CHECK_HEADER, AC_CHECK_HEADERS
1051  More information on proper use.
1052
1053- Writing Test Programs
1054
1055  This sections explains how to write good test sources to use with
1056  AC_COMPILE_IFELSE etc.  It documents AC_LANG_PROGRAM and so forth.
1057
1058- AC_FOO_IFELSE vs. AC_TRY_FOO
1059
1060  Explains why Autoconf moves from AC_TRY_COMPILE etc. to
1061  AC_COMPILE_IFELSE and AC_LANG_PROGRAM etc.
1062
1063** autoreconf
1064
1065- Is more robust to different Gettext installations.
1066
1067- Produces messages (when --verbose) to be understood by Emacs'
1068  compile mode.
1069
1070- Supports -W/--warnings.
1071
1072- -m/--make
1073  Once the GNU Build System reinstalled, run `./config.status
1074  --recheck && ./config.status && make' if possible.
1075
1076** autom4te
1077
1078- Supports --cache, and --no-cache.
1079
1080- ~/.autom4te.cfg makes it possible to disable the caching mechanism
1081  (autom4te.cache).  See `Customizing autom4te' in the documentation.
1082
1083** config.status
1084  Supports --quiet.
1085
1086** Obsolete options
1087
1088  Support for the obsoleted options -m, --macrodir, -l, --localdir is
1089  dropped in favor of the safer --include/--prepend-include scheme.
1090
1091** Macros
1092
1093- New macros
1094  AC_COMPILER_IFELSE, AC_FUNC_MBRTOWC, AC_HEADER_STDBOOL,
1095  AC_LANG_CONFTEST, AC_LANG_SOURCE, AC_LANG_PROGRAM, AC_LANG_CALL,
1096  AC_LANG_FUNC_TRY_LINK, AC_MSG_FAILURE, AC_PREPROC_IFELSE.
1097
1098- Obsoleted
1099  Obsoleted macros are kept for Autoconf backward compatibility, but
1100  should be avoided in configure.ac.  Running autoupdate is advised.
1101  AC_DECL_SYS_SIGLIST.
1102
1103- AC_DEFINE/AC_DEFINE_UNQUOTED
1104
1105  We have to stop using the old compatibility scheme --that tried to
1106  avoid useless backslashes-- because Libtool 1.4.3 contains a
1107
1108  AC_DEFINE([error_t], [int],
1109	    [Define to a type to use for \`error_t' if it is not
1110	     otherwise available.])
1111
1112  We have to quote the single quotes and backslashes with \.  The old
1113  compatibility scheme saw that ` was backslashed, and therefore did
1114  not quote the single quote...  Failure.  Hence, Autoconf 2.54 is not
1115  compatible with Libtool.  Autoconf 2.55 is, but in some cases might
1116  produce more \ than wanted.
1117
1118  Please, note that in the future the same problem will happen with
1119  AC_MSG_*: use `autoreconf -f -Wall'.
1120
1121** Bug Fixes
1122
1123- Portability of the Autoconf package to Solaris.
1124
1125- Spurious warnings caused by config.status.
1126  This bug is benign, but painful: on some systems (typically
1127  FreeBSD), warnings such as:
1128
1129     config.status: creating Makefile
1130     mv: Makefile: set owner/group (was: 1357/0): Operation not permitted
1131
1132  could be issued.  This is fixed.
1133
1134- Parallel Builds
1135  Simultaneous executions of config.status are possible again.
1136
1137- Precious variables accumulation
1138
1139  config.status could stack several copies of the precious variables
1140  assignments.
1141
1142
1143** Plans for later versions
1144
1145- ./configure <host>
1146
1147  The compatibility hooks with the old scheme will be completely
1148  removed.  Please, advice/use `--build', `--host', and `--target'
1149  only.
1150
1151- AC_CHECK_HEADER, AC_CHECK_HEADERS
1152
1153  The tests will be stricter, please make sure your invocations are
1154  valid.
1155
1156- shell functions
1157
1158  Shell functions will gradually be introduced, probably starting with
1159  Autotest.  If you know machines which are in use that you suspect
1160  *not* to support shell functions, please run the test suite of
1161  Autoconf 2.55 on it, and report the results to
1162  bug-autoconf@gnu.org.
1163
1164- AC_MSG_*
1165
1166  Special characters in AC_MSG_* need not be quoted.  Currently,
1167  Autoconf has heuristics to decide when a string is escaped, or has
1168  to be escaped.  This scheme is fragile, and will be removed; the
1169  only risk is uglified messages.  Please, run `autoreconf -f -Wall'
1170  to find occurrences that will be affected.
1171
1172* Major changes in Autoconf 2.54
1173
1174  Released 2002-09-13 by Akim Demaille.
1175
1176** Executables
1177
1178- autoreconf no longer changes the version of the gettext/po/intl
1179  support files. It now adds the files the correspond to the
1180  AM_GNU_GETTEXT_VERSION declared in configure.ac.
1181
1182  Warning: It now relies on the 'autopoint' program, which is part
1183  of GNU gettext 0.11.4 and newer.
1184
1185  Please note that you need to have a GNU gettext version that
1186  corresponds at least to the AM_GNU_GETTEXT_VERSION declared
1187  in configure.ac. You can upgrade to newer GNU gettext versions,
1188  though, without needing to change configure.ac.
1189
1190- The -I DIR or --include=DIR option now appends DIR to the include path
1191  instead of prepending; this is for consistency with other GNU tools.
1192  The new -B DIR or --prepend-include=DIR option has the old behavior.
1193
1194** Macros
1195
1196- AC_OUTPUT
1197  Now handles all the gory details about LIBOBJS and LTLIBOBJS.
1198  Please, remove lines such as
1199
1200	# This is necessary so that .o files in LIBOBJS are also
1201	# built via the ANSI2KNR-filtering rules.
1202	LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
1203
1204  and read the `AC_LIBOBJ vs LIBOBJS' section.  Do not define U in
1205  your Makefiles either.
1206
1207- AC_CONFIG_LINKS now makes copies if it can't make links.
1208
1209- AC_FUNC_FNMATCH now tests only for POSIX compatibility, reverting to
1210  Autoconf 2.13 behavior.  The new macro AC_FUNC_FNMATCH_GNU also
1211  tests for GNU extensions to fnmatch, and replaces fnmatch if needed.
1212
1213- AC_FUNC_SETVBUF_REVERSED no longer fails when cross-compiling.
1214
1215- AC_PROG_CC_STDC is integrated into AC_PROG_CC.
1216
1217- AC_PROG_F77 default search no longer includes cf77 and cfg77.
1218
1219- New macros
1220
1221  AC_C_BACKSLASH_A, AC_CONFIG_LIBOBJ_DIR, AC_GNU_SOURCE,
1222  AC_PROG_EGREP, AC_PROG_FGREP, AC_REPLACE_FNMATCH,
1223  AC_FUNC_FNMATCH_GNU, AC_FUNC_REALLOC, AC_TYPE_MBSTATE_T.
1224
1225- AC_FUNC_GETLOADAVG
1226  looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
1227
1228- AC_FUNC_MALLOC
1229  Now defines HAVE_MALLOC to 0 if `malloc' does not work, and asks
1230  for an AC_LIBOBJ replacement.
1231
1232** Bug fixes
1233
1234- Spurious complaints from `m4_bmatch' about invalid regular
1235  expressions are suppressed.
1236
1237- Empty top_builddirs are properly handled.
1238
1239- AC_CHECK_MEMBER works correctly when the member is an aggregate.
1240
1241- AC_PATH_PROG
1242  Now colon in the optional path arguments are properly handled.
1243
1244** Improved portability
1245
1246- Both Autoconf the package, and the scripts it produces, should run
1247  more reliably with Zsh.  Bear in mind it is the default Bourne shell
1248  on Darwin.
1249
1250- Autoconf and the scripts it produces no longer assume the existence of
1251  the obsolescent commands egrep and fgrep.
1252
1253** Documentation
1254
1255- Limitations of Make
1256  More of them.
1257
1258- GNATS
1259  The GNATS base moved to
1260  http://bugs.gnu.org/cgi-bin/gnatsweb.pl?database=autoconf
1261  (It is no longer available, though.)
1262
1263** Misc.
1264
1265- config.log
1266  Now contains the list of output variables and files (AC_SUBST,
1267  AC_SUBST_FILES).
1268
1269* Major changes in Autoconf 2.53
1270
1271  Released 2002-03-08 by Akim Demaille.
1272
1273** Requirements
1274
1275  Perl 5.005_03 or later is required: autom4te is written in Perl and is
1276  needed by autoconf.  autoheader, autoreconf, ifnames, and autoscan are
1277  rewritten in Perl.
1278
1279** Documentation
1280
1281- AC_INIT
1282  Argument requirements, output variables, defined macros.
1283- M4sugar, M4sh, Autotest
1284  First sketch.
1285- Double quoting macros
1286  AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
1287- Licensing
1288  The Autoconf manual is now distributed under the terms of the GNU FDL.
1289- Section `Hosts and Cross-Compilation'
1290  Explains the rationale for the 2.5x changes in the cross-compilation
1291  chain, and in the relationships between build, host, and target
1292  types.
1293  Emphasizes that `cross-compilation' == `--host is given'.
1294  If you are working on compilers etc., be sure to read this section.
1295- Section `AC_LIBOBJ vs. LIBOBJS'
1296  Explains why assigning LIBOBJS directly is now an error.
1297  Details how to update the code.
1298
1299** configure
1300
1301- $LINENO
1302  Now used instead of hard coded line numbers.
1303  This eases the comparison of `configure's, and diminishes the
1304  pressure over control version archives.
1305  Automatic replacement for shells that don't support this feature.
1306- New output variables
1307  @builddir@, @top_builddir@, @abs_srcdir@, @abs_top_srcdir@, @abs_builddir@,
1308  @abs_top_builddir@.
1309
1310** Emacs
1311
1312  Autoconf and Autotest modes are provided.
1313
1314** Executables
1315
1316- autom4te
1317  New, used by the Autoconf suite to cache and speed up most processing.
1318- --force, -f
1319  Supported by autom4te, autoconf and autoheader.
1320- --include, -I
1321  Replaces --autoconf-dir and --localdir in autoconf, autoheader,
1322  autoupdate, and autoreconf.
1323- autoreconf
1324  No longer passes --cygnus, --foreign, --gnits, --gnu, --include-deps:
1325  automake options are to be given via AUTOMAKE_OPTIONS.
1326- autoreconf
1327  Runs gettextize and libtoolize when appropriate.
1328- autoreconf
1329  --m4dir is no longer supported.
1330- autoreconf
1331  Now runs only in the specified directories, defaulting to `.',
1332  but understands AC_CONFIG_SUBDIRS for dependent directories.
1333  Before, it used to run on all the `configure.ac' found in the
1334  current tree.
1335  Independent packages are properly updated.
1336
1337** Bug fixes
1338
1339- The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
1340- AC_TRY_RUN
1341  Under the user pressure, $? is finally available.  Probably a mistake.
1342- AC_F77_LIBRARY_LDFLAGS now supports the HP/UX f90 compiler.
1343- Precious variables accumulation
1344  config.status could stack several copies of the precious variables
1345  assignments.
1346- AC_PATH_PROG and family.
1347  Works properly when given a literal path.
1348- AC_FUNC_SETPGRP
1349  Somewhere since 2.13, the result had been reversed.
1350
1351** C Macros
1352
1353- AC_C_BIGENDIAN supports the cross-compiling case.
1354- AC_C_BIGENDIAN accepts ACTION-IF-TRUE, ACTION-IF-FALSE, and
1355  ACTION-IF-UNKNOWN arguments.  All are optional, and the default
1356  for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
1357  always did.
1358- AC_C_LONG_DOUBLE now succeeds only if `long double' has more range or
1359  precision than `double'.
1360
1361** Generic macros
1362
1363- AC_INIT
1364  It now defines the preprocessor symbols PACKAGE_NAME,
1365  PACKAGE_TARNAME, PACKAGE_VERSION, PACKAGE_STRING, and
1366  PACKAGE_BUGREPORT.
1367
1368- AC_INIT
1369  Admits a fourth optional parameter: the tar name.
1370
1371- AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS.
1372  Provide the user with srcdir, ac_srcdir, ac_top_srcdir, ac_builddir,
1373  ac_top_builddir, ac_abs_srcdir, ac_abs_top_srcdir, ac_abs_builddir,
1374  ac_abs_top_builddir.
1375
1376- AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS and AC_OUTPUT.
1377  Are much less expensive when using long lists of files.
1378
1379- AC_PREFIX_PROGRAM
1380  Works with shell variables, and non alphanumeric names.
1381
1382** Library macros
1383
1384- AC_FUNC_STRERROR_R now sets STRERROR_R_CHAR_P, not HAVE_WORKING_STRERROR_R,
1385  because POSIX 1003.1-200x draft 7 says strerror_r returns int, not char *.
1386
1387- AC_FUNC_STRTOD substitutes POW_LIB.
1388
1389- AC_FUNC_STRNLEN
1390  New.
1391
1392* Major changes in Autoconf 2.52
1393
1394  Released 2001-07-18 by Akim Demaille.
1395
1396** Documentation
1397- AC_ARG_VAR
1398- Quadrigraphs
1399  This feature was present in autoconf 2.50 but was not documented.
1400  For example, `@<:@' is translated to `[' just before output.  This
1401  is useful when writing strings that contain unbalanced quotes, or
1402  other hard-to-quote constructs.
1403- m4_pattern_forbid, m4_pattern_allow
1404- Tips for upgrading from 2.13.
1405- Using autoscan to maintain a configure.ac.
1406
1407** Default includes
1408- Now include stdint.h.
1409- sys/types.h and sys/stat.h are guarded.
1410- strings.h is included if available, and not conflicting with string.h.
1411
1412** Bug fixes
1413- The test suite is more robust and presents less false failures.
1414- Invocation of GNU M4 now robust to POSIXLY_CORRECT.
1415- configure accepts --prefix='' again.
1416- AC_CHECK_LIB works properly when its first argument is not a
1417  literal.
1418- HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
1419- build_, host_, and target_alias are AC_SUBST as in 2.13.
1420- AC_ARG_VAR properly propagates precious variables inherited from the
1421  environment to ./config.status.
1422- Using --program-suffix/--program-prefix is portable.
1423- Failures to detect the default compiler's output extension are less
1424  likely.
1425- `config.status foo' works properly when `foo' depends on variables
1426  set in an AC_CONFIG_THING INIT-CMD.
1427- autoheader is more robust to broken input.
1428- Fixed Fortran name-mangling and link tests on a number of systems,
1429  e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
1430
1431** Generic macros
1432- AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
1433  specify pre-includes.  In this case, the headers are compiled with
1434  cc, not merely preprocessed by cpp.  Therefore it is the _usability_
1435  of a header which is checked for, not just its availability.
1436- AC_ARG_VAR refuses to run configure when precious variables have
1437  changed.
1438- Versions of compilers are dumped in the logs.
1439- AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
1440
1441** Specific Macros
1442- AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
1443- AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
1444- AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
1445  AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
1446  Be sure to read `Upgrading from Version 2.13' to understand why
1447  running `autoupdate' is needed.
1448- AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
1449  a main-like routine is required/possible when linking C/C++ with
1450  Fortran.  Users of e.g. AC_F77_WRAPPERS should be aware of these.
1451- AC_FUNC_GETPGRG behaves better when cross-compiling.
1452
1453* Major changes in Autoconf 2.51
1454There was no release of Autoconf 2.51 since some packagers had used
1455this version number without permission to ship intermediary versions
1456of 2.50.  The version was skipped to avoid confusion.
1457
1458* Major changes in Autoconf 2.50
1459
1460  Released 2001-05-21 by Akim Demaille.
1461
1462** Lots of bug fixes
1463There have been far too many to enumerate them here.  Check out
1464ChangeLog if you really want to know more.
1465
1466** Improved documentation
1467In particular, portability issues are better covered.
1468
1469** Use of Automake
1470All the standard GNU Makefile targets are supported.  The layout has
1471changed: m4/ holds the M4 extensions Autoconf needs for its
1472configuration, doc/ contains the documentation, and tests/ contains
1473the test suite.
1474
1475** Man pages are provided
1476For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
1477config.guess, config.sub.
1478
1479** autoconf
1480- --trace
1481  Provides a safe and powerful means to trace the macro uses.  This
1482  provide the parsing layer for tools which need to `study'
1483  configure.in.
1484
1485- --warnings
1486  Specify what category of warnings should be enabled.
1487
1488- When recursing into subdirectories, try for configure.gnu before
1489  configure to adapt for packages not using autoconf on case-insensitive
1490  file systems.
1491
1492- Diagnostics
1493  More errors are now caught (circular AC_REQUIRE dependencies,
1494  AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
1495  etc.).  In addition, their location and call stack are given.
1496
1497** autoupdate
1498autoupdate is much more powerful, and is able to provide the glue code
1499which might be needed to move from an old macro to its newer
1500equivalent.
1501
1502You are strongly encouraged to use it to modernize both your
1503`configure.in' and your .m4 extension files.
1504
1505** autoheader
1506The internal machinery of autoheader has completely changed.  As a
1507result, using `acconfig.h' should be considered to be obsoleted, and
1508you are encouraged to get rid of it using the AH macros.
1509
1510** autoreconf
1511Extensive overhaul.
1512
1513** Fortran 77 compilers
1514Globally, the support for Fortran 77 is considerably improved.
1515
1516Support for automatically determining a Fortran 77 compiler's
1517name-mangling scheme.  New CPP macros F77_FUNC and F77_FUNC_ are
1518provided to wrap C/C++ identifiers, thus making it easier and more
1519transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
1520call C/C++ routines.  See the Texinfo documentation for details.
1521
1522** Test suite
1523The test suite no longer uses DejaGNU.  It should be easy to submit
1524test cases in this new framework.
1525
1526** configure
1527- --help, --help=long, -hl
1528  no longer dumps useless items.
1529- --help=short, -hs
1530  lists only specific options.
1531- --help=recursive, -hr
1532  displays the help of all the embedded packages.
1533- Remembers environment variables when reconfiguring.
1534  The previous scheme to set envvar before running configure was
1535    ENV=VAL ./configure
1536  what prevented configure from remembering the environment in which
1537  it was run, therefore --recheck was run in an inconsistent
1538  environment.  Now, one should run
1539    ./configure ENV=VAR
1540  and then --recheck will work properly.  Variables declared with
1541  AC_ARG_VAR are also preserved.
1542- cross-compilation
1543  $build defaults to `config.guess`, $host to $build, and then $target
1544  to $host.
1545  Cross-compilation is a global status of the package, it no longer
1546  depends upon the current language.
1547  Cross compilation is enabled iff the user specified `--host'.
1548  `configure' now fails if it can't run the executables it compiles,
1549  unless cross-compilation is enabled.
1550- Cache file
1551  The cache file is disabled by default.  The new options
1552  `--config-cache', `-C' set the cache to `config.cache'.
1553
1554** config.status
1555- faster
1556  Much faster on most architectures.
1557- concurrent executions
1558  It is safe to use `make -j' with config.status.
1559- human interface improved
1560  It is possible to invoke
1561    ./config.status foobar
1562  instead of the former form (still valid)
1563    CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
1564    CONFIG_FILES=foobar:foo.in:bar.in \
1565    ./config.status
1566  The same holds for configuration headers and links.
1567  You can instantiate unknown files and headers:
1568    ./config.status --header foo.h:foo.h.in --file bar:baz
1569- has a useful --help
1570- accepts special file name "-" for stdin/stdout
1571
1572
1573** Identity Macros
1574- AC_COPYRIGHT
1575  Specify additional copyright information.
1576
1577- AC_INIT
1578  Now expects the identity of the package as argument.
1579
1580** General changes.
1581- Uniform quotation
1582  Most macros, if not all, now strictly follow the `one quotation
1583  level' rule.  This results in a more predictable expansion.
1584
1585- AC_REQUIRE
1586  A sly bug in the AC_REQUIRE machinery, which could produce incorrect
1587  configure scripts, was fixed by Axel Thimm.
1588
1589** Setup Macros
1590- AC_ARG_VAR
1591  Document and ask for the registration of an envvar.
1592
1593- AC_CONFIG_SRCDIR
1594  Specifies the file which `configure' should look for when trying to
1595  find the source tree (used to be handled by AC_INIT).
1596
1597- AC_CONFIG_COMMANDS
1598  To add new actions to config.status.  Should be used instead of
1599  AC_OUTPUT_COMMANDS.
1600
1601- AC_CONFIG_LINKS
1602  Replaces AC_LINK_FILES.
1603
1604- AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
1605  AC_CONFIG_LINKS, and AC_CONFIG_FILES
1606  They now obey sh: you should no longer use shell variables as
1607  argument.  Instead of
1608
1609	test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
1610	AC_CONFIG_SUBDIRS($my_subdirs)
1611
1612  write
1613
1614	if test "$package_foo_enabled" = yes; then
1615	  AC_CONFIG_SUBDIRS(foo)
1616	fi
1617
1618- AC_HELP_STRING
1619  To format an Autoconf macro's help string so that it looks pretty
1620  when the user executes `configure --help'.
1621
1622
1623** Generic Test Macros
1624- AC_CHECK families
1625  The interface of the AC_CHECK families of macros (decl, header,
1626  type, member, func) is now uniform.  They support the same set of
1627  default includes.
1628
1629- AC_CHECK_DECL, AC_CHECK_DECLS
1630  To check whether a symbol is declared.
1631
1632- AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
1633  No longer need a cross-compilation default.
1634
1635- AC_CHECK_TYPE
1636  The test it performs is much more robust than previously, and makes
1637  it possible to test builtin types in addition to typedefs.
1638  It is now schizophrenic:
1639    - AC_CHECK_TYPE(TYPE, REPLACEMENT)
1640      remains for backward compatibility, but its use is discouraged.
1641    - AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
1642      behaves exactly like the other AC_CHECK macros.
1643
1644- AC_CHECK_TYPES
1645  Checks whether given types are supported by the system.
1646
1647- AC_CHECK_MEMBER, AC_CHECK_MEMBERS
1648  Check for given members in aggregates (e.g., pw_gecos in struct
1649  passwd).
1650
1651- AC_PROG_CC_STDC
1652  Checks if the compiler supports ISO C, included when needs special
1653  options.
1654
1655- AC_PROG_CPP
1656  Checking whether the preprocessor indicates missing includes by the
1657  error code. stderr is checked by AC_TRY_CPP only as a fallback.
1658
1659- AC_LANG
1660  Takes a language as argument and replaces AC_LANG_C,
1661  AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
1662
1663- AC_LANG_PUSH, AC_LANG_POP
1664  Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
1665
1666** Specific Macros
1667- AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
1668  AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
1669  AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
1670  New.
1671
1672- AC_FUNC_GETGROUPS
1673  Sets GETGROUPS_LIBS.
1674
1675- AC_FUNC_GETLOADAVG
1676  Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
1677
1678- AC_PROG_LEX
1679  Now integrates `AC_DECL_YYTEXT' which is obsoleted.
1680
1681- AC_SYS_LARGEFILE
1682  Arrange for large-file support.
1683
1684- AC_EXEEXT, AC_OBJEXT
1685  You are no longer expected to use them: their computation is
1686  performed by default.
1687
1688** C++ compatibility
1689  Every macro has been revisited in order to support at best CC=c++.
1690
1691Major changes in Autoconf 2.14:
1692  There was no release of GNU Autoconf 2.14.
1693
1694Major changes in Autoconf 2.13:
1695
1696  Released 1999-05-01 by Ben Elliston.
1697
1698* Support for building on 32-bit Windows systems where the only available C or
1699  C++ compiler is the Microsoft Visual C++ command line compiler
1700  (`cl').  Additional support for building on 32-bit Windows systems which are
1701  using the Cygwin or Mingw32 environments.
1702* Support for alternative object file and executable file extensions.
1703  On 32-bit Windows, for example, these are .obj and .exe. These are discovered
1704  using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
1705  @EXEEXT@ in the output, respectively.
1706* New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
1707  AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
1708  AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
1709* AC_DEFINE now has an optional third argument for a description to be
1710  placed in the config header input file (e.g. config.h.in).
1711* The C++ code fragment compiled for the C++ compiler test had to be
1712  improved to include an explicit return type for main(). This was
1713  causing failures on systems using recent versions of the EGCS C++
1714  compiler.
1715* Fixed an important bug in AC_CHECK_TYPE that would cause a configure
1716  script to report that `sometype_t' was present when only `type_t'
1717  was defined.
1718* Merge of the FSF version of config.guess and config.sub to modernize
1719  these scripts. Add support for a few new hosts in config.guess.
1720  Incorporate latest versions of install-sh, mkinstalldirs and
1721  texinfo.tex from the FSF.
1722* autoreconf is capable of running automake if necessary (and
1723  applicable).
1724* Support for Fortran 77. See the Texinfo documentation for details.
1725* Bug fixes and workarounds for quirky bugs in vendor utilities.
1726
1727Major changes in Autoconf 2.12:
1728
1729  Released 1996-11-26 by David J. MacKenzie
1730
1731* AC_OUTPUT and AC_CONFIG_HEADER can create output files by
1732  concatenating multiple input files separated by colons, like so:
1733  AC_CONFIG_HEADER(config.h:conf.pre:config.h.in:conf.post)
1734  AC_OUTPUT(Makefile:Makefile.in:Makefile.rules)
1735  The arguments may be shell variables, to compute the lists on the fly.
1736* AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
1737* New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
1738* Bug fixes.
1739
1740Major changes in Autoconf 2.11:
1741
1742  Released November 18th, 1996, by David J. MacKenzie
1743
1744* AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
1745  They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
1746* AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
1747* AC_CONFIG_HEADER expands shell variables in its argument.
1748* New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
1749* The "checking..." messages and the source code for test programs that
1750  fail are saved in config.log.
1751* Another workaround has been added for seds with small command length limits.
1752* config.sub and config.guess recognize more system types.
1753* Bug fixes.
1754
1755Major changes in Autoconf 2.10:
1756
1757  Released May 7th, 1996, by Roland McGrath
1758
1759* Bug fixes.
1760* The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
1761  changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
1762
1763Major changes in Autoconf 2.9:
1764
1765  Released March 16th, 1996, by Roland McGrath
1766
1767* Bug fixes.
1768
1769Major changes in Autoconf 2.8:
1770
1771  Released March 8th, 1996, by Roland McGrath
1772
1773* Bug fixes.
1774
1775Major changes in Autoconf 2.7:
1776
1777  Released November 22nd, 1995, by David J. MacKenzie
1778
1779* Bug fixes.
1780
1781Major changes in Autoconf 2.6:
1782
1783  Released November 20th, 1995, by David J. MacKenzie
1784
1785* Bug fixes.
1786
1787Major changes in Autoconf 2.5:
1788
1789  Released November 17th, 1995, by Roland McGrath
1790
1791* New configure options --bindir, --libdir, --datadir, etc., with
1792  corresponding output variables.
1793* New macro: AC_CACHE_CHECK, to make using the cache easier.
1794* config.log contains the command being run as well as any output from it.
1795* AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
1796* AC_PROG_INSTALL doesn't cache a name for install-sh, for sharing caches.
1797* AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
1798  AC_CHECK_TOOL can search a path other than $PATH.
1799* AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
1800
1801Major changes in Autoconf 2.4:
1802
1803  Released June 14th, 1995, by David J. MacKenzie
1804
1805* Fix a few bugs found by Emacs testers.
1806
1807Major changes in Autoconf 2.3:
1808
1809  Released March 27th, 1995, by David J. MacKenzie
1810
1811* Fix the cleanup trap in several ways.
1812* Handle C compilers that are picky about option placement.
1813* ifnames gets the version number from the right directory.
1814
1815Major changes in Autoconf 2.2:
1816
1817  Released March 8th, 1995, by David J. MacKenzie
1818
1819* The ifnames utility is much faster but requires a "new awk" interpreter.
1820* AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
1821  library before existing libs, not after, in case it uses them.
1822* New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
1823* Lots of bug fixes.
1824* Many additions to the TODO file :-)
1825
1826Major changes in Autoconf 2.1:
1827
1828  Released November 4th, 1994, by David J. MacKenzie
1829
1830* Fix C++ problems.
1831* More explanations in the manual.
1832* Fix a spurious failure in the testsuite.
1833* Clarify some warning messages.
1834* autoreconf by default only rebuilds configure and config.h.in files
1835  that are older than any of their particular input files; there is a
1836  --force option to use after installing a new version of Autoconf.
1837
1838Thanks to everybody who's submitted changes and additions to Autoconf!
1839I've incorporated many of them, and am still considering others for
1840future releases -- but I didn't want to postpone this release indefinitely.
1841
1842Caution: don't indiscriminately rebuild configure scripts with
1843Autoconf version 2.  Some configure.in files need minor adjustments to
1844work with it; the documentation has a chapter on upgrading.  A few
1845configure.in files, including those for GNU Emacs and the GNU C
1846Library, need major changes because they relied on undocumented
1847internals of version 1.  Future releases of those packages will have
1848updated configure.in files.
1849
1850It's best to use GNU M4 1.3 (or later) with Autoconf version 2.
1851Autoconf now makes heavy use of M4 diversions, which were implemented
1852inefficiently in GNU M4 releases before 1.3.
1853
1854Major changes in Autoconf 2.0:
1855
1856  Released October 26th, 1994, by David J. MacKenzie
1857
1858** New copyright terms:
1859* There are no restrictions on distribution or use of configure scripts.
1860
1861** Documentation:
1862* Autoconf manual is reorganized to make information easier to find
1863  and has several new indexes.
1864* INSTALL is reorganized and clearer and is now made from Texinfo source.
1865
1866** New utilities:
1867* autoscan to generate a preliminary configure.in for a package by
1868  scanning its source code for commonly used nonportable functions,
1869  programs, and header files.
1870* ifnames to list the symbols used in #if and #ifdef directives in a
1871  source tree.
1872* autoupdate to update a configure.in to use the version 2 macro names.
1873* autoreconf to recursively remake configure and configuration header
1874  files in a source tree.
1875
1876** Changed utilities:
1877* autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
1878* autoconf and autoheader can look for package-local definition files
1879  in an alternate directory.
1880
1881** New macros:
1882* AC_CACHE_VAL to share results of tests between configure runs.
1883* AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
1884  that macros invoked with AC_REQUIRE don't interrupt other macros.
1885* AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
1886  support deciding unguessable features based on the host and target types.
1887* AC_CONFIG_SUBDIRS to recursively configure a source tree.
1888* AC_ARG_PROGRAM to use the options --program-prefix,
1889  --program-suffix, and --program-transform-name to change the names
1890  of programs being installed.
1891* AC_PREFIX_DEFAULT to change the default installation prefix.
1892* AC_TRY_COMPILE to compile a test program without linking it.
1893* AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
1894* AC_CHECK_LIB to check for a particular function and library.
1895* AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
1896  whether or not the test succeeds.  They obsolete AC_CHECKING and AC_VERBOSE.
1897* AC_SUBST_FILE to insert one file into another.
1898* AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
1899* AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
1900* AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
1901* AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
1902
1903** Changed macros:
1904* Many macros renamed systematically, but old names are accepted for
1905  backward compatibility.
1906* AC_OUTPUT adds the "automatically generated" comment to
1907  non-Makefiles where it finds @configure_input@ in an input file, to
1908  support files with various comment syntaxes.
1909* AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
1910  files when they are not enclosed in @ signs.
1911* AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
1912  override the file name "config.status".
1913* AC_OUTPUT takes an optional argument for passing variables from
1914  configure to config.status.
1915* AC_OUTPUT and AC_CONFIG_HEADER allow you to override the input-file names.
1916* AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
1917  CPPFLAGS, and LDFLAGS from the environment.
1918* AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
1919* AC_PROG_INSTALL looks for install-sh or install.sh in the directory
1920  specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
1921  srcdir/../.. by default.
1922* AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
1923* AC_DEFINE no longer prints anything, because of the new result reporting
1924  mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
1925* AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
1926* AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
1927  --enable- and --with- options.
1928* AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
1929  execute on success or failure.
1930* Checking for C functions in C++ works.
1931
1932** Removed macros:
1933* AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
1934  better maintained with them.
1935* AC_ARG_ARRAY removed because no one was likely using it.
1936* AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
1937  take arguments, for consistency with all of the other specific checks.
1938
1939** New files:
1940* Comes with config.sub and config.guess, and uses them optionally.
1941* Uses config.cache to cache test results.  An alternate cache file
1942  can be selected with the --cache-file=FILE option.
1943* Uses optional shell scripts $prefix/share/config.site and
1944  $prefix/etc/config.site to perform site or system specific initializations.
1945* configure saves compiler output to ./config.log for debugging.
1946* New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
1947* acsite.m4 is the new name for the system-wide aclocal.m4.
1948* Has a DejaGnu test suite.
1949
1950Major changes in Autoconf 1.11:
1951
1952* AC_PROG_INSTALL calls install.sh with the -c option.
1953* AC_SET_MAKE cleans up after itself.
1954* AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
1955* AC_OUTPUT prevents shells from looking in PATH for config.status.
1956
1957Plus a few other bug fixes.
1958
1959Major changes in Autoconf 1.10:
1960
1961* autoheader uses config.h.bot if present, analogous to config.h.top.
1962* AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
1963  never uses cp.
1964* AC_PROG_CXX looks for cxx as a C++ compiler.
1965
1966Plus several bugs fixed.
1967
1968Major changes in Autoconf 1.9:
1969
1970* AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
1971* AC_SIZEOF_TYPE generates the cpp symbol name automatically,
1972  and autoheader generates entries for those names automatically.
1973* AC_FIND_X gets the result from xmkmf correctly.
1974* AC_FIND_X assumes no X if --without-x was given.
1975* AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
1976* AC_PROG_INSTALL finds OSF/1 installbsd.
1977
1978Major changes in Autoconf 1.8:
1979
1980** New macros:
1981* New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
1982  AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
1983  for checking both C++ and C features in one configure script.
1984* New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
1985* New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
1986  AC_SET_MAKE, AC_ENABLE.
1987
1988** Changed macros:
1989* AC_FIND_X looks for X in more places.
1990* AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
1991  install.sh is distributed with Autoconf.
1992* AC_DECLARE_YYTEXT has been removed because it can't work, pending
1993  a rewrite of quoting in AC_DEFINE.
1994* AC_OUTPUT adds its comments in C format when substituting in C files.
1995* AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
1996
1997** New or changed command line options:
1998* configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
1999* configure accepts --without-PACKAGE, which sets withval=no.
2000* configure accepts --x-includes=DIR and --x-libraries=DIR.
2001* Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
2002* configure accepts --help, --version, --silent/--quiet, --no-create options.
2003* configure accepts and ignores most other Cygnus configure options, and
2004  warns about unknown options.
2005* config.status accepts --help, --version options.
2006
2007** File names and other changes:
2008* Relative srcdir values are not made absolute.
2009* The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
2010* Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
2011* autoheader optionally copies config.h.top to the beginning of config.h.in.
2012* The example Makefile dependencies for configure et al. work better.
2013* Namespace cleanup: all shell variables used internally by Autoconf
2014  have names beginning with `ac_'.
2015
2016More big improvements are in process for future releases, but have not
2017yet been (variously) finished, integrated, tested, or documented enough
2018to release yet.
2019
2020Major changes in Autoconf 1.7:
2021
2022* New macro AC_OBSOLETE.
2023* Bugs in Makefile.in fixed.
2024* AC_LONG_FILE_NAMES improved.
2025
2026Major changes in Autoconf 1.6:
2027
2028* New macro AC_LONG_64_BITS.
2029* Multiple .h files can be created.
2030* AC_FIND_X looks for X files directly if it doesn't find xmkmf.
2031* AC_ALLOCA defines C_ALLOCA if using alloca.c.
2032* --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
2033* Unused --no-create option to configure removed.
2034* autoheader doesn't change the timestamp of its output file if
2035  the file didn't change.
2036* All macros that look for libraries now use AC_HAVE_LIBRARY.
2037* config.status checks three optional environment variables to
2038  modify its behavior.
2039* The usual bug fixes.
2040
2041Major changes in Autoconf 1.5:
2042
2043* New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
2044* autoconf and autoheader scripts have GNU standards conforming
2045  --version and --help options (they print their message and exit).
2046* Many bug fixes.
2047
2048Major changes in Autoconf 1.4:
2049
2050* New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
2051  AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
2052* autoconf and autoheader use the M4 environment variable to determine the
2053  name of the M4 program to use.
2054* The --macrodir option to autoconf and autoheader specifies the directory
2055  in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
2056* autoconf and autoheader can take `-' as their file names, which means to
2057  read stdin as input.
2058* Resulting configure scripts can take a --verbose option which causes them
2059  to print the results of their tests.
2060* AC_DEFINE quotes its second argument in such a way that spaces, magic
2061  shell characters, etc. will be preserved during various stages of
2062  expansion done by the shell.  If you don't want this, use
2063  AC_DEFINE_UNQUOTED instead.
2064* Much textual processing done with external calls to tr and sed have been
2065  internalized with builtin M4 `patsubst' and `translit' calls.
2066* AC_OUTPUT doesn't hardwire the file names it outputs.  Instead, you can
2067  set the shell variables `gen_files' and `gen_config' to the list of
2068  file names to output.
2069* AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
2070  "lex.yy" or "lexyy", depending on the system.
2071* AC_PROGRAMS_CHECK takes an optional third arg.  If given, it is used as
2072  the default value.
2073* If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
2074* AC_CONST works much more reliably on more systems.
2075* Many bug fixes.
2076
2077Major changes in Autoconf 1.3:
2078
2079configure no longer requires awk for packages that use a config.h.
2080Support handling --with-PACKAGE options.
2081New `autoheader' script to create `config.h.in' from `configure.in'.
2082Ignore troublesome -lucb and -lPW when searching for alloca.
2083Rename --exec_prefix to --exec-prefix for GNU standards conformance.
2084Improve detection of STDC library.
2085Add AC_HAVE_LIBRARY to check for non-default libraries.
2086Function checking should work with future GNU libc releases.
2087
2088Major changes in Autoconf 1.2:
2089
2090The --srcdir option is now usually unnecessary.
2091Add a file containing sample comments describing CPP macros.
2092A comment in config.status tells which host it was configured on.
2093Substituted variable values can now contain commas.
2094Fix bugs in various feature checks.
2095
2096Major changes in Autoconf 1.1:
2097
2098Added AC_STRCOLL macro.
2099Made AC_GETLOADAVG check for more things.
2100AC_OUTPUT argument is now optional.
2101Various bug fixes.
2102
2103-----
2104
2105Copyright (C) 1993-1996, 1998-2012 Free Software Foundation, Inc.
2106
2107Copying and distribution of this file, with or without modification,
2108are permitted in any medium without royalty provided the copyright
2109notice and this notice are preserved.  This file is offered as-is,
2110without warranty of any kind.
2111
2112Local Variables:
2113mode: outline
2114End:
2115