1# gnulib-common.m4 serial 62
2dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7AC_PREREQ([2.62])
8
9# gl_COMMON
10# is expanded unconditionally through gnulib-tool magic.
11AC_DEFUN([gl_COMMON], [
12  dnl Use AC_REQUIRE here, so that the code is expanded once only.
13  AC_REQUIRE([gl_00GNULIB])
14  AC_REQUIRE([gl_COMMON_BODY])
15  AC_REQUIRE([gl_ZZGNULIB])
16])
17AC_DEFUN([gl_COMMON_BODY], [
18  AH_VERBATIM([_GL_GNUC_PREREQ],
19[/* True if the compiler says it groks GNU C version MAJOR.MINOR.  */
20#if defined __GNUC__ && defined __GNUC_MINOR__
21# define _GL_GNUC_PREREQ(major, minor) \
22    ((major) < __GNUC__ + ((minor) <= __GNUC_MINOR__))
23#else
24# define _GL_GNUC_PREREQ(major, minor) 0
25#endif
26])
27  AH_VERBATIM([_Noreturn],
28[/* The _Noreturn keyword of C11.  */
29#ifndef _Noreturn
30# if (defined __cplusplus \
31      && ((201103 <= __cplusplus && !(__GNUC__ == 4 && __GNUC_MINOR__ == 7)) \
32          || (defined _MSC_VER && 1900 <= _MSC_VER)) \
33      && 0)
34    /* [[noreturn]] is not practically usable, because with it the syntax
35         extern _Noreturn void func (...);
36       would not be valid; such a declaration would only be valid with 'extern'
37       and '_Noreturn' swapped, or without the 'extern' keyword.  However, some
38       AIX system header files and several gnulib header files use precisely
39       this syntax with 'extern'.  */
40#  define _Noreturn [[noreturn]]
41# elif ((!defined __cplusplus || defined __clang__) \
42        && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0)  \
43            || _GL_GNUC_PREREQ (4, 7) \
44            || (defined __apple_build_version__ \
45                ? 6000000 <= __apple_build_version__ \
46                : 3 < __clang_major__ + (5 <= __clang_minor__))))
47   /* _Noreturn works as-is.  */
48# elif _GL_GNUC_PREREQ (2, 8) || defined __clang__ || 0x5110 <= __SUNPRO_C
49#  define _Noreturn __attribute__ ((__noreturn__))
50# elif 1200 <= (defined _MSC_VER ? _MSC_VER : 0)
51#  define _Noreturn __declspec (noreturn)
52# else
53#  define _Noreturn
54# endif
55#endif
56])
57  AH_VERBATIM([isoc99_inline],
58[/* Work around a bug in Apple GCC 4.0.1 build 5465: In C99 mode, it supports
59   the ISO C 99 semantics of 'extern inline' (unlike the GNU C semantics of
60   earlier versions), but does not display it by setting __GNUC_STDC_INLINE__.
61   __APPLE__ && __MACH__ test for Mac OS X.
62   __APPLE_CC__ tests for the Apple compiler and its version.
63   __STDC_VERSION__ tests for the C99 mode.  */
64#if defined __APPLE__ && defined __MACH__ && __APPLE_CC__ >= 5465 && !defined __cplusplus && __STDC_VERSION__ >= 199901L && !defined __GNUC_STDC_INLINE__
65# define __GNUC_STDC_INLINE__ 1
66#endif])
67  AH_VERBATIM([attribute],
68[/* Attributes.  */
69#ifdef __has_attribute
70# define _GL_HAS_ATTRIBUTE(attr) __has_attribute (__##attr##__)
71#else
72# define _GL_HAS_ATTRIBUTE(attr) _GL_ATTR_##attr
73# define _GL_ATTR_alloc_size _GL_GNUC_PREREQ (4, 3)
74# define _GL_ATTR_always_inline _GL_GNUC_PREREQ (3, 2)
75# define _GL_ATTR_artificial _GL_GNUC_PREREQ (4, 3)
76# define _GL_ATTR_cold _GL_GNUC_PREREQ (4, 3)
77# define _GL_ATTR_const _GL_GNUC_PREREQ (2, 95)
78# define _GL_ATTR_deprecated _GL_GNUC_PREREQ (3, 1)
79# define _GL_ATTR_diagnose_if 0
80# define _GL_ATTR_error _GL_GNUC_PREREQ (4, 3)
81# define _GL_ATTR_externally_visible _GL_GNUC_PREREQ (4, 1)
82# define _GL_ATTR_fallthrough _GL_GNUC_PREREQ (7, 0)
83# define _GL_ATTR_format _GL_GNUC_PREREQ (2, 7)
84# define _GL_ATTR_leaf _GL_GNUC_PREREQ (4, 6)
85# ifdef _ICC
86#  define _GL_ATTR_may_alias 0
87# else
88#  define _GL_ATTR_may_alias _GL_GNUC_PREREQ (3, 3)
89# endif
90# define _GL_ATTR_malloc _GL_GNUC_PREREQ (3, 0)
91# define _GL_ATTR_noinline _GL_GNUC_PREREQ (3, 1)
92# define _GL_ATTR_nonnull _GL_GNUC_PREREQ (3, 3)
93# define _GL_ATTR_nonstring _GL_GNUC_PREREQ (8, 0)
94# define _GL_ATTR_nothrow _GL_GNUC_PREREQ (3, 3)
95# define _GL_ATTR_packed _GL_GNUC_PREREQ (2, 7)
96# define _GL_ATTR_pure _GL_GNUC_PREREQ (2, 96)
97# define _GL_ATTR_returns_nonnull _GL_GNUC_PREREQ (4, 9)
98# define _GL_ATTR_sentinel _GL_GNUC_PREREQ (4, 0)
99# define _GL_ATTR_unused _GL_GNUC_PREREQ (2, 7)
100# define _GL_ATTR_warn_unused_result _GL_GNUC_PREREQ (3, 4)
101#endif
102
103]dnl There is no _GL_ATTRIBUTE_ALIGNED; use stdalign's _Alignas instead.
104[
105#if _GL_HAS_ATTRIBUTE (alloc_size)
106# define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
107#else
108# define _GL_ATTRIBUTE_ALLOC_SIZE(args)
109#endif
110
111#if _GL_HAS_ATTRIBUTE (always_inline)
112# define _GL_ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__))
113#else
114# define _GL_ATTRIBUTE_ALWAYS_INLINE
115#endif
116
117#if _GL_HAS_ATTRIBUTE (artificial)
118# define _GL_ATTRIBUTE_ARTIFICIAL __attribute__ ((__artificial__))
119#else
120# define _GL_ATTRIBUTE_ARTIFICIAL
121#endif
122
123/* Avoid __attribute__ ((cold)) on MinGW; see thread starting at
124   <https://lists.gnu.org/r/emacs-devel/2019-04/msg01152.html>.
125   Also, Oracle Studio 12.6 requires 'cold' not '__cold__'.  */
126#if _GL_HAS_ATTRIBUTE (cold) && !defined __MINGW32__
127# ifndef __SUNPRO_C
128#  define _GL_ATTRIBUTE_COLD __attribute__ ((__cold__))
129# else
130#  define _GL_ATTRIBUTE_COLD __attribute__ ((cold))
131# endif
132#else
133# define _GL_ATTRIBUTE_COLD
134#endif
135
136#if _GL_HAS_ATTRIBUTE (const)
137# define _GL_ATTRIBUTE_CONST __attribute__ ((__const__))
138#else
139# define _GL_ATTRIBUTE_CONST
140#endif
141
142#if 201710L < __STDC_VERSION__
143# define _GL_ATTRIBUTE_DEPRECATED [[__deprecated__]]
144#elif _GL_HAS_ATTRIBUTE (deprecated)
145# define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
146#else
147# define _GL_ATTRIBUTE_DEPRECATED
148#endif
149
150#if _GL_HAS_ATTRIBUTE (error)
151# define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__error__ (msg)))
152# define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__warning__ (msg)))
153#elif _GL_HAS_ATTRIBUTE (diagnose_if)
154# define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__diagnose_if__ (1, msg, "error")))
155# define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__diagnose_if__ (1, msg, "warning")))
156#else
157# define _GL_ATTRIBUTE_ERROR(msg)
158# define _GL_ATTRIBUTE_WARNING(msg)
159#endif
160
161#if _GL_HAS_ATTRIBUTE (externally_visible)
162# define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE __attribute__ ((externally_visible))
163#else
164# define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
165#endif
166
167/* FALLTHROUGH is special, because it always expands to something.  */
168#if 201710L < __STDC_VERSION__
169# define _GL_ATTRIBUTE_FALLTHROUGH [[__fallthrough__]]
170#elif _GL_HAS_ATTRIBUTE (fallthrough)
171# define _GL_ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__))
172#else
173# define _GL_ATTRIBUTE_FALLTHROUGH ((void) 0)
174#endif
175
176#if _GL_HAS_ATTRIBUTE (format)
177# define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
178#else
179# define _GL_ATTRIBUTE_FORMAT(spec)
180#endif
181
182#if _GL_HAS_ATTRIBUTE (leaf)
183# define _GL_ATTRIBUTE_LEAF __attribute__ ((__leaf__))
184#else
185# define _GL_ATTRIBUTE_LEAF
186#endif
187
188/* Oracle Studio 12.6 mishandles may_alias despite __has_attribute OK.  */
189#if _GL_HAS_ATTRIBUTE (may_alias) && !defined __SUNPRO_C
190# define _GL_ATTRIBUTE_MAY_ALIAS __attribute__ ((__may_alias__))
191#else
192# define _GL_ATTRIBUTE_MAY_ALIAS
193#endif
194
195#if 201710L < __STDC_VERSION__
196# define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]]
197#elif _GL_HAS_ATTRIBUTE (unused)
198# define _GL_ATTRIBUTE_MAYBE_UNUSED __attribute__ ((__unused__))
199#else
200# define _GL_ATTRIBUTE_MAYBE_UNUSED
201#endif
202/* Earlier spellings of this macro.  */
203#define _GL_UNUSED _GL_ATTRIBUTE_MAYBE_UNUSED
204#define _UNUSED_PARAMETER_ _GL_ATTRIBUTE_MAYBE_UNUSED
205
206#if _GL_HAS_ATTRIBUTE (malloc)
207# define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
208#else
209# define _GL_ATTRIBUTE_MALLOC
210#endif
211
212#if 201710L < __STDC_VERSION__
213# define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]]
214#elif _GL_HAS_ATTRIBUTE (warn_unused_result)
215# define _GL_ATTRIBUTE_NODISCARD __attribute__ ((__warn_unused_result__))
216#else
217# define _GL_ATTRIBUTE_NODISCARD
218#endif
219
220#if _GL_HAS_ATTRIBUTE (noinline)
221# define _GL_ATTRIBUTE_NOINLINE __attribute__ ((__noinline__))
222#else
223# define _GL_ATTRIBUTE_NOINLINE
224#endif
225
226#if _GL_HAS_ATTRIBUTE (nonnull)
227# define _GL_ATTRIBUTE_NONNULL(args) __attribute__ ((__nonnull__ args))
228#else
229# define _GL_ATTRIBUTE_NONNULL(args)
230#endif
231
232#if _GL_HAS_ATTRIBUTE (nonstring)
233# define _GL_ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__))
234#else
235# define _GL_ATTRIBUTE_NONSTRING
236#endif
237
238/* There is no _GL_ATTRIBUTE_NORETURN; use _Noreturn instead.  */
239
240#if _GL_HAS_ATTRIBUTE (nothrow) && !defined __cplusplus
241# define _GL_ATTRIBUTE_NOTHROW __attribute__ ((__nothrow__))
242#else
243# define _GL_ATTRIBUTE_NOTHROW
244#endif
245
246#if _GL_HAS_ATTRIBUTE (packed)
247# define _GL_ATTRIBUTE_PACKED __attribute__ ((__packed__))
248#else
249# define _GL_ATTRIBUTE_PACKED
250#endif
251
252#if _GL_HAS_ATTRIBUTE (pure)
253# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
254#else
255# define _GL_ATTRIBUTE_PURE
256#endif
257
258#if _GL_HAS_ATTRIBUTE (returns_nonnull)
259# define _GL_ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__))
260#else
261# define _GL_ATTRIBUTE_RETURNS_NONNULL
262#endif
263
264#if _GL_HAS_ATTRIBUTE (sentinel)
265# define _GL_ATTRIBUTE_SENTINEL(pos) __attribute__ ((__sentinel__ pos))
266#else
267# define _GL_ATTRIBUTE_SENTINEL(pos)
268#endif
269
270]dnl There is no _GL_ATTRIBUTE_VISIBILITY; see m4/visibility.m4 instead.
271[
272/* To support C++ as well as C, use _GL_UNUSED_LABEL with trailing ';'.  */
273#if !defined __cplusplus || _GL_GNUC_PREREQ (4, 5)
274# define _GL_UNUSED_LABEL _GL_ATTRIBUTE_MAYBE_UNUSED
275#else
276# define _GL_UNUSED_LABEL
277#endif
278])
279  AH_VERBATIM([async_safe],
280[/* The _GL_ASYNC_SAFE marker should be attached to functions that are
281   signal handlers (for signals other than SIGABRT, SIGPIPE) or can be
282   invoked from such signal handlers.  Such functions have some restrictions:
283     * All functions that it calls should be marked _GL_ASYNC_SAFE as well,
284       or should be listed as async-signal-safe in POSIX
285       <https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04>
286       section 2.4.3.  Note that malloc(), sprintf(), and fwrite(), in
287       particular, are NOT async-signal-safe.
288     * All memory locations (variables and struct fields) that these functions
289       access must be marked 'volatile'.  This holds for both read and write
290       accesses.  Otherwise the compiler might optimize away stores to and
291       reads from such locations that occur in the program, depending on its
292       data flow analysis.  For example, when the program contains a loop
293       that is intended to inspect a variable set from within a signal handler
294           while (!signal_occurred)
295             ;
296       the compiler is allowed to transform this into an endless loop if the
297       variable 'signal_occurred' is not declared 'volatile'.
298   Additionally, recall that:
299     * A signal handler should not modify errno (except if it is a handler
300       for a fatal signal and ends by raising the same signal again, thus
301       provoking the termination of the process).  If it invokes a function
302       that may clobber errno, it needs to save and restore the value of
303       errno.  */
304#define _GL_ASYNC_SAFE
305])
306  AH_VERBATIM([micro_optimizations],
307[/* _GL_CMP (n1, n2) performs a three-valued comparison on n1 vs. n2, where
308   n1 and n2 are expressions without side effects, that evaluate to real
309   numbers (excluding NaN).
310   It returns
311     1  if n1 > n2
312     0  if n1 == n2
313     -1 if n1 < n2
314   The naïve code   (n1 > n2 ? 1 : n1 < n2 ? -1 : 0)  produces a conditional
315   jump with nearly all GCC versions up to GCC 10.
316   This variant     (n1 < n2 ? -1 : n1 > n2)  produces a conditional with many
317   GCC versions up to GCC 9.
318   The better code  (n1 > n2) - (n1 < n2)  from Hacker's Delight § 2-9
319   avoids conditional jumps in all GCC versions >= 3.4.  */
320#define _GL_CMP(n1, n2) (((n1) > (n2)) - ((n1) < (n2)))
321])
322  dnl Hint which direction to take regarding cross-compilation guesses:
323  dnl When a user installs a program on a platform they are not intimately
324  dnl familiar with, --enable-cross-guesses=conservative is the appropriate
325  dnl choice.  It implements the "If we don't know, assume the worst" principle.
326  dnl However, when an operating system developer (on a platform which is not
327  dnl yet known to gnulib) builds packages for their platform, they want to
328  dnl expose, not hide, possible platform bugs; in this case,
329  dnl --enable-cross-guesses=risky is the appropriate choice.
330  dnl Sets the variables
331  dnl gl_cross_guess_normal    (to be used when 'yes' is good and 'no' is bad),
332  dnl gl_cross_guess_inverted  (to be used when 'no' is good and 'yes' is bad).
333  AC_ARG_ENABLE([cross-guesses],
334    [AS_HELP_STRING([--enable-cross-guesses={conservative|risky}],
335       [specify policy for cross-compilation guesses])],
336    [if test "x$enableval" != xconservative && test "x$enableval" != xrisky; then
337       AC_MSG_WARN([invalid argument supplied to --enable-cross-guesses])
338       enableval=conservative
339     fi
340     gl_cross_guesses="$enableval"],
341    [gl_cross_guesses=conservative])
342  if test $gl_cross_guesses = risky; then
343    gl_cross_guess_normal="guessing yes"
344    gl_cross_guess_inverted="guessing no"
345  else
346    gl_cross_guess_normal="guessing no"
347    gl_cross_guess_inverted="guessing yes"
348  fi
349  dnl Preparation for running test programs:
350  dnl Tell glibc to write diagnostics from -D_FORTIFY_SOURCE=2 to stderr, not
351  dnl to /dev/tty, so they can be redirected to log files.  Such diagnostics
352  dnl arise e.g., in the macros gl_PRINTF_DIRECTIVE_N, gl_SNPRINTF_DIRECTIVE_N.
353  LIBC_FATAL_STDERR_=1
354  export LIBC_FATAL_STDERR_
355])
356
357# gl_MODULE_INDICATOR_CONDITION
358# expands to a C preprocessor expression that evaluates to 1 or 0, depending
359# whether a gnulib module that has been requested shall be considered present
360# or not.
361m4_define([gl_MODULE_INDICATOR_CONDITION], [1])
362
363# gl_MODULE_INDICATOR_SET_VARIABLE([modulename])
364# sets the shell variable that indicates the presence of the given module to
365# a C preprocessor expression that will evaluate to 1.
366AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE],
367[
368  gl_MODULE_INDICATOR_SET_VARIABLE_AUX(
369    [GNULIB_[]m4_translit([[$1]],
370                          [abcdefghijklmnopqrstuvwxyz./-],
371                          [ABCDEFGHIJKLMNOPQRSTUVWXYZ___])],
372    [gl_MODULE_INDICATOR_CONDITION])
373])
374
375# gl_MODULE_INDICATOR_SET_VARIABLE_AUX([variable])
376# modifies the shell variable to include the gl_MODULE_INDICATOR_CONDITION.
377# The shell variable's value is a C preprocessor expression that evaluates
378# to 0 or 1.
379AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE_AUX],
380[
381  m4_if(m4_defn([gl_MODULE_INDICATOR_CONDITION]), [1],
382    [
383     dnl Simplify the expression VALUE || 1 to 1.
384     $1=1
385    ],
386    [gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR([$1],
387                                             [gl_MODULE_INDICATOR_CONDITION])])
388])
389
390# gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR([variable], [condition])
391# modifies the shell variable to include the given condition.  The shell
392# variable's value is a C preprocessor expression that evaluates to 0 or 1.
393AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR],
394[
395  dnl Simplify the expression 1 || CONDITION to 1.
396  if test "$[]$1" != 1; then
397    dnl Simplify the expression 0 || CONDITION to CONDITION.
398    if test "$[]$1" = 0; then
399      $1=$2
400    else
401      $1="($[]$1 || $2)"
402    fi
403  fi
404])
405
406# gl_MODULE_INDICATOR([modulename])
407# defines a C macro indicating the presence of the given module
408# in a location where it can be used.
409#                                             |  Value  |   Value   |
410#                                             | in lib/ | in tests/ |
411# --------------------------------------------+---------+-----------+
412# Module present among main modules:          |    1    |     1     |
413# --------------------------------------------+---------+-----------+
414# Module present among tests-related modules: |    0    |     1     |
415# --------------------------------------------+---------+-----------+
416# Module not present at all:                  |    0    |     0     |
417# --------------------------------------------+---------+-----------+
418AC_DEFUN([gl_MODULE_INDICATOR],
419[
420  AC_DEFINE_UNQUOTED([GNULIB_]m4_translit([[$1]],
421      [abcdefghijklmnopqrstuvwxyz./-],
422      [ABCDEFGHIJKLMNOPQRSTUVWXYZ___]),
423    [gl_MODULE_INDICATOR_CONDITION],
424    [Define to a C preprocessor expression that evaluates to 1 or 0,
425     depending whether the gnulib module $1 shall be considered present.])
426])
427
428# gl_MODULE_INDICATOR_FOR_TESTS([modulename])
429# defines a C macro indicating the presence of the given module
430# in lib or tests. This is useful to determine whether the module
431# should be tested.
432#                                             |  Value  |   Value   |
433#                                             | in lib/ | in tests/ |
434# --------------------------------------------+---------+-----------+
435# Module present among main modules:          |    1    |     1     |
436# --------------------------------------------+---------+-----------+
437# Module present among tests-related modules: |    1    |     1     |
438# --------------------------------------------+---------+-----------+
439# Module not present at all:                  |    0    |     0     |
440# --------------------------------------------+---------+-----------+
441AC_DEFUN([gl_MODULE_INDICATOR_FOR_TESTS],
442[
443  AC_DEFINE([GNULIB_TEST_]m4_translit([[$1]],
444      [abcdefghijklmnopqrstuvwxyz./-],
445      [ABCDEFGHIJKLMNOPQRSTUVWXYZ___]), [1],
446    [Define to 1 when the gnulib module $1 should be tested.])
447])
448
449# gl_ASSERT_NO_GNULIB_POSIXCHECK
450# asserts that there will never be a need to #define GNULIB_POSIXCHECK.
451# and thereby enables an optimization of configure and config.h.
452# Used by Emacs.
453AC_DEFUN([gl_ASSERT_NO_GNULIB_POSIXCHECK],
454[
455  dnl Override gl_WARN_ON_USE_PREPARE.
456  dnl But hide this definition from 'aclocal'.
457  AC_DEFUN([gl_W][ARN_ON_USE_PREPARE], [])
458])
459
460# gl_ASSERT_NO_GNULIB_TESTS
461# asserts that there will be no gnulib tests in the scope of the configure.ac
462# and thereby enables an optimization of config.h.
463# Used by Emacs.
464AC_DEFUN([gl_ASSERT_NO_GNULIB_TESTS],
465[
466  dnl Override gl_MODULE_INDICATOR_FOR_TESTS.
467  AC_DEFUN([gl_MODULE_INDICATOR_FOR_TESTS], [])
468])
469
470# Test whether <features.h> exists.
471# Set HAVE_FEATURES_H.
472AC_DEFUN([gl_FEATURES_H],
473[
474  AC_CHECK_HEADERS_ONCE([features.h])
475  if test $ac_cv_header_features_h = yes; then
476    HAVE_FEATURES_H=1
477  else
478    HAVE_FEATURES_H=0
479  fi
480  AC_SUBST([HAVE_FEATURES_H])
481])
482
483# gl_PROG_CC_C99
484# Modifies the value of the shell variable CC in an attempt to make $CC
485# understand ISO C99 source code.
486AC_DEFUN([gl_PROG_CC_C99],
487[
488  dnl Just use AC_PROG_CC_C99.
489  dnl When AC_PROG_CC_C99 and AC_PROG_CC_STDC are used together, the substituted
490  dnl value of CC will contain the C99 enabling options twice. But this is only
491  dnl a cosmetic problem.
492  dnl With Autoconf >= 2.69c, use AC_PROG_CC since it implies AC_PROG_CC_C99;
493  dnl this avoids a "warning: The macro `AC_PROG_CC_C99' is obsolete."
494  m4_version_prereq([2.69c],
495    [AC_REQUIRE([AC_PROG_CC])],
496    [AC_REQUIRE([AC_PROG_CC_C99])])
497])
498
499# gl_PROG_AR_RANLIB
500# Determines the values for AR, ARFLAGS, RANLIB that fit with the compiler.
501# The user can set the variables AR, ARFLAGS, RANLIB if he wants to override
502# the values.
503AC_DEFUN([gl_PROG_AR_RANLIB],
504[
505  dnl Minix 3 comes with two toolchains: The Amsterdam Compiler Kit compiler
506  dnl as "cc", and GCC as "gcc". They have different object file formats and
507  dnl library formats. In particular, the GNU binutils programs ar and ranlib
508  dnl produce libraries that work only with gcc, not with cc.
509  AC_REQUIRE([AC_PROG_CC])
510  dnl The '][' hides this use from 'aclocal'.
511  AC_BEFORE([$0], [A][M_PROG_AR])
512  AC_CACHE_CHECK([for Minix Amsterdam compiler], [gl_cv_c_amsterdam_compiler],
513    [
514      AC_EGREP_CPP([Amsterdam],
515        [
516#ifdef __ACK__
517Amsterdam
518#endif
519        ],
520        [gl_cv_c_amsterdam_compiler=yes],
521        [gl_cv_c_amsterdam_compiler=no])
522    ])
523
524  dnl Don't compete with AM_PROG_AR's decision about AR/ARFLAGS if we are not
525  dnl building with __ACK__.
526  if test $gl_cv_c_amsterdam_compiler = yes; then
527    if test -z "$AR"; then
528      AR='cc -c.a'
529    fi
530    if test -z "$ARFLAGS"; then
531      ARFLAGS='-o'
532    fi
533  else
534    dnl AM_PROG_AR was added in automake v1.11.2.  AM_PROG_AR does not AC_SUBST
535    dnl ARFLAGS variable (it is filed into Makefile.in directly by automake
536    dnl script on-demand, if not specified by ./configure of course).
537    dnl Don't AC_REQUIRE the AM_PROG_AR otherwise the code for __ACK__ above
538    dnl will be ignored.  Also, pay attention to call AM_PROG_AR in else block
539    dnl because AM_PROG_AR is written so it could re-set AR variable even for
540    dnl __ACK__.  It may seem like its easier to avoid calling the macro here,
541    dnl but we need to AC_SUBST both AR/ARFLAGS (thus those must have some good
542    dnl default value and automake should usually know them).
543    dnl
544    dnl The '][' hides this use from 'aclocal'.
545    m4_ifdef([A][M_PROG_AR], [A][M_PROG_AR], [:])
546  fi
547
548  dnl In case the code above has not helped with setting AR/ARFLAGS, use
549  dnl Automake-documented default values for AR and ARFLAGS, but prefer
550  dnl ${host}-ar over ar (useful for cross-compiling).
551  AC_CHECK_TOOL([AR], [ar], [ar])
552  if test -z "$ARFLAGS"; then
553    ARFLAGS='cr'
554  fi
555
556  AC_SUBST([AR])
557  AC_SUBST([ARFLAGS])
558  if test -z "$RANLIB"; then
559    if test $gl_cv_c_amsterdam_compiler = yes; then
560      RANLIB=':'
561    else
562      dnl Use the ranlib program if it is available.
563      AC_PROG_RANLIB
564    fi
565  fi
566  AC_SUBST([RANLIB])
567])
568
569# AC_C_RESTRICT
570# This definition is copied from post-2.69 Autoconf and overrides the
571# AC_C_RESTRICT macro from autoconf 2.60..2.69.  It can be removed
572# once autoconf >= 2.70 can be assumed.  It's painful to check version
573# numbers, and in practice this macro is more up-to-date than Autoconf
574# is, so override Autoconf unconditionally.
575AC_DEFUN([AC_C_RESTRICT],
576[AC_CACHE_CHECK([for C/C++ restrict keyword], [ac_cv_c_restrict],
577  [ac_cv_c_restrict=no
578   # The order here caters to the fact that C++ does not require restrict.
579   for ac_kw in __restrict __restrict__ _Restrict restrict; do
580     AC_COMPILE_IFELSE(
581      [AC_LANG_PROGRAM(
582         [[typedef int *int_ptr;
583           int foo (int_ptr $ac_kw ip) { return ip[0]; }
584           int bar (int [$ac_kw]); /* Catch GCC bug 14050.  */
585           int bar (int ip[$ac_kw]) { return ip[0]; }
586         ]],
587         [[int s[1];
588           int *$ac_kw t = s;
589           t[0] = 0;
590           return foo (t) + bar (t);
591         ]])],
592      [ac_cv_c_restrict=$ac_kw])
593     test "$ac_cv_c_restrict" != no && break
594   done
595  ])
596 AH_VERBATIM([restrict],
597[/* Define to the equivalent of the C99 'restrict' keyword, or to
598   nothing if this is not supported.  Do not define if restrict is
599   supported directly.  */
600#undef restrict
601/* Work around a bug in older versions of Sun C++, which did not
602   #define __restrict__ or support _Restrict or __restrict__
603   even though the corresponding Sun C compiler ended up with
604   "#define restrict _Restrict" or "#define restrict __restrict__"
605   in the previous line.  This workaround can be removed once
606   we assume Oracle Developer Studio 12.5 (2016) or later.  */
607#if defined __SUNPRO_CC && !defined __RESTRICT && !defined __restrict__
608# define _Restrict
609# define __restrict__
610#endif])
611 case $ac_cv_c_restrict in
612   restrict) ;;
613   no) AC_DEFINE([restrict], []) ;;
614   *)  AC_DEFINE_UNQUOTED([restrict], [$ac_cv_c_restrict]) ;;
615 esac
616])# AC_C_RESTRICT
617
618# gl_BIGENDIAN
619# is like AC_C_BIGENDIAN, except that it can be AC_REQUIREd.
620# Note that AC_REQUIRE([AC_C_BIGENDIAN]) does not work reliably because some
621# macros invoke AC_C_BIGENDIAN with arguments.
622AC_DEFUN([gl_BIGENDIAN],
623[
624  AC_C_BIGENDIAN
625])
626
627# A temporary file descriptor.
628# Must be less than 10, because dash 0.5.8 does not support redirections
629# with multi-digit file descriptors.
630m4_define([GL_TMP_FD], 9)
631
632# gl_SILENT(command)
633# executes command, but without the normal configure output.
634# This is useful when you want to invoke AC_CACHE_CHECK (or AC_CHECK_FUNC etc.)
635# inside another AC_CACHE_CHECK.
636AC_DEFUN([gl_SILENT],
637[
638  exec GL_TMP_FD>&AS_MESSAGE_FD AS_MESSAGE_FD>/dev/null
639  $1
640  exec AS_MESSAGE_FD>&GL_TMP_FD GL_TMP_FD>&-
641])
642
643# gl_CACHE_VAL_SILENT(cache-id, command-to-set-it)
644# is like AC_CACHE_VAL(cache-id, command-to-set-it), except that it does not
645# output a spurious "(cached)" mark in the midst of other configure output.
646# This macro should be used instead of AC_CACHE_VAL when it is not surrounded
647# by an AC_MSG_CHECKING/AC_MSG_RESULT pair.
648AC_DEFUN([gl_CACHE_VAL_SILENT],
649[
650  gl_SILENT([
651    AC_CACHE_VAL([$1], [$2])
652  ])
653])
654
655dnl Expands to some code for use in .c programs that, on native Windows, defines
656dnl the Microsoft deprecated alias function names to the underscore-prefixed
657dnl actual function names. With this macro, these function names are available
658dnl without linking with '-loldnames' and without generating warnings.
659dnl Usage: Use it after all system header files are included.
660dnl          #include <...>
661dnl          #include <...>
662dnl          ]GL_MDA_DEFINES[
663dnl          ...
664AC_DEFUN([GL_MDA_DEFINES],[
665AC_REQUIRE([_GL_MDA_DEFINES])
666[$gl_mda_defines]
667])
668AC_DEFUN([_GL_MDA_DEFINES],
669[gl_mda_defines='
670#if defined _WIN32 && !defined __CYGWIN__
671#define access    _access
672#define chdir     _chdir
673#define chmod     _chmod
674#define close     _close
675#define creat     _creat
676#define dup       _dup
677#define dup2      _dup2
678#define ecvt      _ecvt
679#define execl     _execl
680#define execle    _execle
681#define execlp    _execlp
682#define execv     _execv
683#define execve    _execve
684#define execvp    _execvp
685#define execvpe   _execvpe
686#define fcloseall _fcloseall
687#define fcvt      _fcvt
688#define fdopen    _fdopen
689#define fileno    _fileno
690#define gcvt      _gcvt
691#define getcwd    _getcwd
692#define getpid    _getpid
693#define getw      _getw
694#define isatty    _isatty
695#define j0        _j0
696#define j1        _j1
697#define jn        _jn
698#define lfind     _lfind
699#define lsearch   _lsearch
700#define lseek     _lseek
701#define memccpy   _memccpy
702#define mkdir     _mkdir
703#define mktemp    _mktemp
704#define open      _open
705#define putenv    _putenv
706#define putw      _putw
707#define read      _read
708#define rmdir     _rmdir
709#define strdup    _strdup
710#define swab      _swab
711#define tempnam   _tempnam
712#define tzset     _tzset
713#define umask     _umask
714#define unlink    _unlink
715#define utime     _utime
716#define wcsdup    _wcsdup
717#define write     _write
718#define y0        _y0
719#define y1        _y1
720#define yn        _yn
721#endif
722'
723])
724