1# gnulib-common.m4 serial 52 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) || 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_error _GL_GNUC_PREREQ (4, 3) 80# define _GL_ATTR_externally_visible _GL_GNUC_PREREQ (4, 1) 81# define _GL_ATTR_fallthrough _GL_GNUC_PREREQ (7, 0) 82# define _GL_ATTR_format _GL_GNUC_PREREQ (2, 7) 83# define _GL_ATTR_leaf _GL_GNUC_PREREQ (4, 6) 84# ifdef _ICC 85# define _GL_ATTR_may_alias 0 86# else 87# define _GL_ATTR_may_alias _GL_GNUC_PREREQ (3, 3) 88# endif 89# define _GL_ATTR_malloc _GL_GNUC_PREREQ (3, 0) 90# define _GL_ATTR_noinline _GL_GNUC_PREREQ (3, 1) 91# define _GL_ATTR_nonnull _GL_GNUC_PREREQ (3, 3) 92# define _GL_ATTR_nonstring _GL_GNUC_PREREQ (8, 0) 93# define _GL_ATTR_nothrow _GL_GNUC_PREREQ (3, 3) 94# define _GL_ATTR_packed _GL_GNUC_PREREQ (2, 7) 95# define _GL_ATTR_pure _GL_GNUC_PREREQ (2, 96) 96# define _GL_ATTR_returns_nonnull _GL_GNUC_PREREQ (4, 9) 97# define _GL_ATTR_sentinel _GL_GNUC_PREREQ (4, 0) 98# define _GL_ATTR_unused _GL_GNUC_PREREQ (2, 7) 99# define _GL_ATTR_warn_unused_result _GL_GNUC_PREREQ (3, 4) 100#endif 101 102]dnl There is no _GL_ATTRIBUTE_ALIGNED; use stdalign's _Alignas instead. 103[ 104#if _GL_HAS_ATTRIBUTE (alloc_size) 105# define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args)) 106#else 107# define _GL_ATTRIBUTE_ALLOC_SIZE(args) 108#endif 109 110#if _GL_HAS_ATTRIBUTE (always_inline) 111# define _GL_ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__)) 112#else 113# define _GL_ATTRIBUTE_ALWAYS_INLINE 114#endif 115 116#if _GL_HAS_ATTRIBUTE (artificial) 117# define _GL_ATTRIBUTE_ARTIFICIAL __attribute__ ((__artificial__)) 118#else 119# define _GL_ATTRIBUTE_ARTIFICIAL 120#endif 121 122/* Avoid __attribute__ ((cold)) on MinGW; see thread starting at 123 <https://lists.gnu.org/r/emacs-devel/2019-04/msg01152.html>. */ 124#if _GL_HAS_ATTRIBUTE (cold) && !defined __MINGW32__ 125# define _GL_ATTRIBUTE_COLD __attribute__ ((__cold__)) 126#else 127# define _GL_ATTRIBUTE_COLD 128#endif 129 130#if _GL_HAS_ATTRIBUTE (const) 131# define _GL_ATTRIBUTE_CONST __attribute__ ((__const__)) 132#else 133# define _GL_ATTRIBUTE_CONST 134#endif 135 136#if 201710L < __STDC_VERSION__ 137# define _GL_ATTRIBUTE_DEPRECATED [[__deprecated__]] 138#elif _GL_HAS_ATTRIBUTE (deprecated) 139# define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__)) 140#else 141# define _GL_ATTRIBUTE_DEPRECATED 142#endif 143 144#if _GL_HAS_ATTRIBUTE (error) 145# define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__error__ (msg))) 146# define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__warning__ (msg))) 147#else 148# define _GL_ATTRIBUTE_ERROR(msg) 149# define _GL_ATTRIBUTE_WARNING(msg) 150#endif 151 152#if _GL_HAS_ATTRIBUTE (externally_visible) 153# define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE __attribute__ ((externally_visible)) 154#else 155# define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE 156#endif 157 158/* FALLTHROUGH is special, because it always expands to something. */ 159#if 201710L < __STDC_VERSION__ 160# define _GL_ATTRIBUTE_FALLTHROUGH [[__fallthrough__]] 161#elif _GL_HAS_ATTRIBUTE (fallthrough) 162# define _GL_ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__)) 163#else 164# define _GL_ATTRIBUTE_FALLTHROUGH ((void) 0) 165#endif 166 167#if _GL_HAS_ATTRIBUTE (format) 168# define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec)) 169#else 170# define _GL_ATTRIBUTE_FORMAT(spec) 171#endif 172 173#if _GL_HAS_ATTRIBUTE (leaf) 174# define _GL_ATTRIBUTE_LEAF __attribute__ ((__leaf__)) 175#else 176# define _GL_ATTRIBUTE_LEAF 177#endif 178 179#if _GL_HAS_ATTRIBUTE (may_alias) 180# define _GL_ATTRIBUTE_MAY_ALIAS __attribute__ ((__may_alias__)) 181#else 182# define _GL_ATTRIBUTE_MAY_ALIAS 183#endif 184 185#if 201710L < __STDC_VERSION__ 186# define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]] 187#elif _GL_HAS_ATTRIBUTE (unused) 188# define _GL_ATTRIBUTE_MAYBE_UNUSED __attribute__ ((__unused__)) 189#else 190# define _GL_ATTRIBUTE_MAYBE_UNUSED 191#endif 192/* Earlier spellings of this macro. */ 193#define _GL_UNUSED _GL_ATTRIBUTE_MAYBE_UNUSED 194#define _UNUSED_PARAMETER_ _GL_ATTRIBUTE_MAYBE_UNUSED 195 196#if _GL_HAS_ATTRIBUTE (malloc) 197# define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__)) 198#else 199# define _GL_ATTRIBUTE_MALLOC 200#endif 201 202#if 201710L < __STDC_VERSION__ 203# define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]] 204#elif _GL_HAS_ATTRIBUTE (warn_unused_result) 205# define _GL_ATTRIBUTE_NODISCARD __attribute__ ((__warn_unused_result__)) 206#else 207# define _GL_ATTRIBUTE_NODISCARD 208#endif 209 210#if _GL_HAS_ATTRIBUTE (noinline) 211# define _GL_ATTRIBUTE_NOINLINE __attribute__ ((__noinline__)) 212#else 213# define _GL_ATTRIBUTE_NOINLINE 214#endif 215 216#if _GL_HAS_ATTRIBUTE (nonnull) 217# define _GL_ATTRIBUTE_NONNULL(args) __attribute__ ((__nonnull__ args)) 218#else 219# define _GL_ATTRIBUTE_NONNULL(args) 220#endif 221 222#if _GL_HAS_ATTRIBUTE (nonstring) 223# define _GL_ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__)) 224#else 225# define _GL_ATTRIBUTE_NONSTRING 226#endif 227 228/* There is no _GL_ATTRIBUTE_NORETURN; use _Noreturn instead. */ 229 230#if _GL_HAS_ATTRIBUTE (nothrow) && !defined __cplusplus 231# define _GL_ATTRIBUTE_NOTHROW __attribute__ ((__nothrow__)) 232#else 233# define _GL_ATTRIBUTE_NOTHROW 234#endif 235 236#if _GL_HAS_ATTRIBUTE (packed) 237# define _GL_ATTRIBUTE_PACKED __attribute__ ((__packed__)) 238#else 239# define _GL_ATTRIBUTE_PACKED 240#endif 241 242#if _GL_HAS_ATTRIBUTE (pure) 243# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__)) 244#else 245# define _GL_ATTRIBUTE_PURE 246#endif 247 248#if _GL_HAS_ATTRIBUTE (returns_nonnull) 249# define _GL_ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__)) 250#else 251# define _GL_ATTRIBUTE_RETURNS_NONNULL 252#endif 253 254#if _GL_HAS_ATTRIBUTE (sentinel) 255# define _GL_ATTRIBUTE_SENTINEL(pos) __attribute__ ((__sentinel__ pos)) 256#else 257# define _GL_ATTRIBUTE_SENTINEL(pos) 258#endif 259 260]dnl There is no _GL_ATTRIBUTE_VISIBILITY; see m4/visibility.m4 instead. 261[ 262/* To support C++ as well as C, use _GL_UNUSED_LABEL with trailing ';'. */ 263#if !defined __cplusplus || _GL_GNUC_PREREQ (4, 5) 264# define _GL_UNUSED_LABEL _GL_ATTRIBUTE_MAYBE_UNUSED 265#else 266# define _GL_UNUSED_LABEL 267#endif 268]) 269 AH_VERBATIM([async_safe], 270[/* The _GL_ASYNC_SAFE marker should be attached to functions that are 271 signal handlers (for signals other than SIGABRT, SIGPIPE) or can be 272 invoked from such signal handlers. Such functions have some restrictions: 273 * All functions that it calls should be marked _GL_ASYNC_SAFE as well, 274 or should be listed as async-signal-safe in POSIX 275 <https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04> 276 section 2.4.3. Note that malloc(), sprintf(), and fwrite(), in 277 particular, are NOT async-signal-safe. 278 * All memory locations (variables and struct fields) that these functions 279 access must be marked 'volatile'. This holds for both read and write 280 accesses. Otherwise the compiler might optimize away stores to and 281 reads from such locations that occur in the program, depending on its 282 data flow analysis. For example, when the program contains a loop 283 that is intended to inspect a variable set from within a signal handler 284 while (!signal_occurred) 285 ; 286 the compiler is allowed to transform this into an endless loop if the 287 variable 'signal_occurred' is not declared 'volatile'. 288 Additionally, recall that: 289 * A signal handler should not modify errno (except if it is a handler 290 for a fatal signal and ends by raising the same signal again, thus 291 provoking the termination of the process). If it invokes a function 292 that may clobber errno, it needs to save and restore the value of 293 errno. */ 294#define _GL_ASYNC_SAFE 295]) 296 AH_VERBATIM([micro_optimizations], 297[/* _GL_CMP (n1, n2) performs a three-valued comparison on n1 vs. n2. 298 It returns 299 1 if n1 > n2 300 0 if n1 == n2 301 -1 if n1 < n2 302 The naïve code (n1 > n2 ? 1 : n1 < n2 ? -1 : 0) produces a conditional 303 jump with nearly all GCC versions up to GCC 10. 304 This variant (n1 < n2 ? -1 : n1 > n2) produces a conditional with many 305 GCC versions up to GCC 9. 306 The better code (n1 > n2) - (n1 < n2) from Hacker's Delight § 2-9 307 avoids conditional jumps in all GCC versions >= 3.4. */ 308#define _GL_CMP(n1, n2) (((n1) > (n2)) - ((n1) < (n2))) 309]) 310 dnl Hint which direction to take regarding cross-compilation guesses: 311 dnl When a user installs a program on a platform they are not intimately 312 dnl familiar with, --enable-cross-guesses=conservative is the appropriate 313 dnl choice. It implements the "If we don't know, assume the worst" principle. 314 dnl However, when an operating system developer (on a platform which is not 315 dnl yet known to gnulib) builds packages for their platform, they want to 316 dnl expose, not hide, possible platform bugs; in this case, 317 dnl --enable-cross-guesses=risky is the appropriate choice. 318 dnl Sets the variables 319 dnl gl_cross_guess_normal (to be used when 'yes' is good and 'no' is bad), 320 dnl gl_cross_guess_inverted (to be used when 'no' is good and 'yes' is bad). 321 AC_ARG_ENABLE([cross-guesses], 322 [AS_HELP_STRING([--enable-cross-guesses={conservative|risky}], 323 [specify policy for cross-compilation guesses])], 324 [if test "x$enableval" != xconservative && test "x$enableval" != xrisky; then 325 AC_MSG_WARN([invalid argument supplied to --enable-cross-guesses]) 326 enableval=conservative 327 fi 328 gl_cross_guesses="$enableval"], 329 [gl_cross_guesses=conservative]) 330 if test $gl_cross_guesses = risky; then 331 gl_cross_guess_normal="guessing yes" 332 gl_cross_guess_inverted="guessing no" 333 else 334 gl_cross_guess_normal="guessing no" 335 gl_cross_guess_inverted="guessing yes" 336 fi 337 dnl Preparation for running test programs: 338 dnl Tell glibc to write diagnostics from -D_FORTIFY_SOURCE=2 to stderr, not 339 dnl to /dev/tty, so they can be redirected to log files. Such diagnostics 340 dnl arise e.g., in the macros gl_PRINTF_DIRECTIVE_N, gl_SNPRINTF_DIRECTIVE_N. 341 LIBC_FATAL_STDERR_=1 342 export LIBC_FATAL_STDERR_ 343]) 344 345# gl_MODULE_INDICATOR_CONDITION 346# expands to a C preprocessor expression that evaluates to 1 or 0, depending 347# whether a gnulib module that has been requested shall be considered present 348# or not. 349m4_define([gl_MODULE_INDICATOR_CONDITION], [1]) 350 351# gl_MODULE_INDICATOR_SET_VARIABLE([modulename]) 352# sets the shell variable that indicates the presence of the given module to 353# a C preprocessor expression that will evaluate to 1. 354AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE], 355[ 356 gl_MODULE_INDICATOR_SET_VARIABLE_AUX( 357 [GNULIB_[]m4_translit([[$1]], 358 [abcdefghijklmnopqrstuvwxyz./-], 359 [ABCDEFGHIJKLMNOPQRSTUVWXYZ___])], 360 [gl_MODULE_INDICATOR_CONDITION]) 361]) 362 363# gl_MODULE_INDICATOR_SET_VARIABLE_AUX([variable]) 364# modifies the shell variable to include the gl_MODULE_INDICATOR_CONDITION. 365# The shell variable's value is a C preprocessor expression that evaluates 366# to 0 or 1. 367AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE_AUX], 368[ 369 m4_if(m4_defn([gl_MODULE_INDICATOR_CONDITION]), [1], 370 [ 371 dnl Simplify the expression VALUE || 1 to 1. 372 $1=1 373 ], 374 [gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR([$1], 375 [gl_MODULE_INDICATOR_CONDITION])]) 376]) 377 378# gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR([variable], [condition]) 379# modifies the shell variable to include the given condition. The shell 380# variable's value is a C preprocessor expression that evaluates to 0 or 1. 381AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR], 382[ 383 dnl Simplify the expression 1 || CONDITION to 1. 384 if test "$[]$1" != 1; then 385 dnl Simplify the expression 0 || CONDITION to CONDITION. 386 if test "$[]$1" = 0; then 387 $1=$2 388 else 389 $1="($[]$1 || $2)" 390 fi 391 fi 392]) 393 394# gl_MODULE_INDICATOR([modulename]) 395# defines a C macro indicating the presence of the given module 396# in a location where it can be used. 397# | Value | Value | 398# | in lib/ | in tests/ | 399# --------------------------------------------+---------+-----------+ 400# Module present among main modules: | 1 | 1 | 401# --------------------------------------------+---------+-----------+ 402# Module present among tests-related modules: | 0 | 1 | 403# --------------------------------------------+---------+-----------+ 404# Module not present at all: | 0 | 0 | 405# --------------------------------------------+---------+-----------+ 406AC_DEFUN([gl_MODULE_INDICATOR], 407[ 408 AC_DEFINE_UNQUOTED([GNULIB_]m4_translit([[$1]], 409 [abcdefghijklmnopqrstuvwxyz./-], 410 [ABCDEFGHIJKLMNOPQRSTUVWXYZ___]), 411 [gl_MODULE_INDICATOR_CONDITION], 412 [Define to a C preprocessor expression that evaluates to 1 or 0, 413 depending whether the gnulib module $1 shall be considered present.]) 414]) 415 416# gl_MODULE_INDICATOR_FOR_TESTS([modulename]) 417# defines a C macro indicating the presence of the given module 418# in lib or tests. This is useful to determine whether the module 419# should be tested. 420# | Value | Value | 421# | in lib/ | in tests/ | 422# --------------------------------------------+---------+-----------+ 423# Module present among main modules: | 1 | 1 | 424# --------------------------------------------+---------+-----------+ 425# Module present among tests-related modules: | 1 | 1 | 426# --------------------------------------------+---------+-----------+ 427# Module not present at all: | 0 | 0 | 428# --------------------------------------------+---------+-----------+ 429AC_DEFUN([gl_MODULE_INDICATOR_FOR_TESTS], 430[ 431 AC_DEFINE([GNULIB_TEST_]m4_translit([[$1]], 432 [abcdefghijklmnopqrstuvwxyz./-], 433 [ABCDEFGHIJKLMNOPQRSTUVWXYZ___]), [1], 434 [Define to 1 when the gnulib module $1 should be tested.]) 435]) 436 437# gl_ASSERT_NO_GNULIB_POSIXCHECK 438# asserts that there will never be a need to #define GNULIB_POSIXCHECK. 439# and thereby enables an optimization of configure and config.h. 440# Used by Emacs. 441AC_DEFUN([gl_ASSERT_NO_GNULIB_POSIXCHECK], 442[ 443 dnl Override gl_WARN_ON_USE_PREPARE. 444 dnl But hide this definition from 'aclocal'. 445 AC_DEFUN([gl_W][ARN_ON_USE_PREPARE], []) 446]) 447 448# gl_ASSERT_NO_GNULIB_TESTS 449# asserts that there will be no gnulib tests in the scope of the configure.ac 450# and thereby enables an optimization of config.h. 451# Used by Emacs. 452AC_DEFUN([gl_ASSERT_NO_GNULIB_TESTS], 453[ 454 dnl Override gl_MODULE_INDICATOR_FOR_TESTS. 455 AC_DEFUN([gl_MODULE_INDICATOR_FOR_TESTS], []) 456]) 457 458# Test whether <features.h> exists. 459# Set HAVE_FEATURES_H. 460AC_DEFUN([gl_FEATURES_H], 461[ 462 AC_CHECK_HEADERS_ONCE([features.h]) 463 if test $ac_cv_header_features_h = yes; then 464 HAVE_FEATURES_H=1 465 else 466 HAVE_FEATURES_H=0 467 fi 468 AC_SUBST([HAVE_FEATURES_H]) 469]) 470 471# AS_VAR_IF(VAR, VALUE, [IF-MATCH], [IF-NOT-MATCH]) 472# ---------------------------------------------------- 473# Backport of autoconf-2.63b's macro. 474# Remove this macro when we can assume autoconf >= 2.64. 475m4_ifndef([AS_VAR_IF], 476[m4_define([AS_VAR_IF], 477[AS_IF([test x"AS_VAR_GET([$1])" = x""$2], [$3], [$4])])]) 478 479# gl_PROG_CC_C99 480# Modifies the value of the shell variable CC in an attempt to make $CC 481# understand ISO C99 source code. 482# This is like AC_PROG_CC_C99, except that 483# - AC_PROG_CC_C99 does not mix well with AC_PROG_CC_STDC 484# <https://lists.gnu.org/r/bug-gnulib/2011-09/msg00367.html>, 485# but many more packages use AC_PROG_CC_STDC than AC_PROG_CC_C99 486# <https://lists.gnu.org/r/bug-gnulib/2011-09/msg00441.html>. 487# Remaining problems: 488# - When AC_PROG_CC_STDC is invoked twice, it adds the C99 enabling options 489# to CC twice 490# <https://lists.gnu.org/r/bug-gnulib/2011-09/msg00431.html>. 491# - AC_PROG_CC_STDC is likely to change now that C11 is an ISO standard. 492AC_DEFUN([gl_PROG_CC_C99], 493[ 494 dnl Change that version number to the minimum Autoconf version that supports 495 dnl mixing AC_PROG_CC_C99 calls with AC_PROG_CC_STDC calls. 496 m4_version_prereq([9.0], 497 [AC_REQUIRE([AC_PROG_CC_C99])], 498 [AC_REQUIRE([AC_PROG_CC_STDC])]) 499]) 500 501# gl_PROG_AR_RANLIB 502# Determines the values for AR, ARFLAGS, RANLIB that fit with the compiler. 503# The user can set the variables AR, ARFLAGS, RANLIB if he wants to override 504# the values. 505AC_DEFUN([gl_PROG_AR_RANLIB], 506[ 507 dnl Minix 3 comes with two toolchains: The Amsterdam Compiler Kit compiler 508 dnl as "cc", and GCC as "gcc". They have different object file formats and 509 dnl library formats. In particular, the GNU binutils programs ar and ranlib 510 dnl produce libraries that work only with gcc, not with cc. 511 AC_REQUIRE([AC_PROG_CC]) 512 dnl The '][' hides this use from 'aclocal'. 513 AC_BEFORE([$0], [A][M_PROG_AR]) 514 AC_CACHE_CHECK([for Minix Amsterdam compiler], [gl_cv_c_amsterdam_compiler], 515 [ 516 AC_EGREP_CPP([Amsterdam], 517 [ 518#ifdef __ACK__ 519Amsterdam 520#endif 521 ], 522 [gl_cv_c_amsterdam_compiler=yes], 523 [gl_cv_c_amsterdam_compiler=no]) 524 ]) 525 526 dnl Don't compete with AM_PROG_AR's decision about AR/ARFLAGS if we are not 527 dnl building with __ACK__. 528 if test $gl_cv_c_amsterdam_compiler = yes; then 529 if test -z "$AR"; then 530 AR='cc -c.a' 531 fi 532 if test -z "$ARFLAGS"; then 533 ARFLAGS='-o' 534 fi 535 else 536 dnl AM_PROG_AR was added in automake v1.11.2. AM_PROG_AR does not AC_SUBST 537 dnl ARFLAGS variable (it is filed into Makefile.in directly by automake 538 dnl script on-demand, if not specified by ./configure of course). 539 dnl Don't AC_REQUIRE the AM_PROG_AR otherwise the code for __ACK__ above 540 dnl will be ignored. Also, pay attention to call AM_PROG_AR in else block 541 dnl because AM_PROG_AR is written so it could re-set AR variable even for 542 dnl __ACK__. It may seem like its easier to avoid calling the macro here, 543 dnl but we need to AC_SUBST both AR/ARFLAGS (thus those must have some good 544 dnl default value and automake should usually know them). 545 dnl 546 dnl The '][' hides this use from 'aclocal'. 547 m4_ifdef([A][M_PROG_AR], [A][M_PROG_AR], [:]) 548 fi 549 550 dnl In case the code above has not helped with setting AR/ARFLAGS, use 551 dnl Automake-documented default values for AR and ARFLAGS, but prefer 552 dnl ${host}-ar over ar (useful for cross-compiling). 553 AC_CHECK_TOOL([AR], [ar], [ar]) 554 if test -z "$ARFLAGS"; then 555 ARFLAGS='cr' 556 fi 557 558 AC_SUBST([AR]) 559 AC_SUBST([ARFLAGS]) 560 if test -z "$RANLIB"; then 561 if test $gl_cv_c_amsterdam_compiler = yes; then 562 RANLIB=':' 563 else 564 dnl Use the ranlib program if it is available. 565 AC_PROG_RANLIB 566 fi 567 fi 568 AC_SUBST([RANLIB]) 569]) 570 571# AC_C_RESTRICT 572# This definition is copied from post-2.69 Autoconf and overrides the 573# AC_C_RESTRICT macro from autoconf 2.60..2.69. It can be removed 574# once autoconf >= 2.70 can be assumed. It's painful to check version 575# numbers, and in practice this macro is more up-to-date than Autoconf 576# is, so override Autoconf unconditionally. 577AC_DEFUN([AC_C_RESTRICT], 578[AC_CACHE_CHECK([for C/C++ restrict keyword], [ac_cv_c_restrict], 579 [ac_cv_c_restrict=no 580 # The order here caters to the fact that C++ does not require restrict. 581 for ac_kw in __restrict __restrict__ _Restrict restrict; do 582 AC_COMPILE_IFELSE( 583 [AC_LANG_PROGRAM( 584 [[typedef int *int_ptr; 585 int foo (int_ptr $ac_kw ip) { return ip[0]; } 586 int bar (int [$ac_kw]); /* Catch GCC bug 14050. */ 587 int bar (int ip[$ac_kw]) { return ip[0]; } 588 ]], 589 [[int s[1]; 590 int *$ac_kw t = s; 591 t[0] = 0; 592 return foo (t) + bar (t); 593 ]])], 594 [ac_cv_c_restrict=$ac_kw]) 595 test "$ac_cv_c_restrict" != no && break 596 done 597 ]) 598 AH_VERBATIM([restrict], 599[/* Define to the equivalent of the C99 'restrict' keyword, or to 600 nothing if this is not supported. Do not define if restrict is 601 supported directly. */ 602#undef restrict 603/* Work around a bug in older versions of Sun C++, which did not 604 #define __restrict__ or support _Restrict or __restrict__ 605 even though the corresponding Sun C compiler ended up with 606 "#define restrict _Restrict" or "#define restrict __restrict__" 607 in the previous line. This workaround can be removed once 608 we assume Oracle Developer Studio 12.5 (2016) or later. */ 609#if defined __SUNPRO_CC && !defined __RESTRICT && !defined __restrict__ 610# define _Restrict 611# define __restrict__ 612#endif]) 613 case $ac_cv_c_restrict in 614 restrict) ;; 615 no) AC_DEFINE([restrict], []) ;; 616 *) AC_DEFINE_UNQUOTED([restrict], [$ac_cv_c_restrict]) ;; 617 esac 618])# AC_C_RESTRICT 619 620# gl_BIGENDIAN 621# is like AC_C_BIGENDIAN, except that it can be AC_REQUIREd. 622# Note that AC_REQUIRE([AC_C_BIGENDIAN]) does not work reliably because some 623# macros invoke AC_C_BIGENDIAN with arguments. 624AC_DEFUN([gl_BIGENDIAN], 625[ 626 AC_C_BIGENDIAN 627]) 628 629# gl_SILENT(command) 630# executes command, but without the normal configure output. 631AC_DEFUN([gl_SILENT], 632[ 633 { 634 $1 635 } AS_MESSAGE_FD>/dev/null 636]) 637 638# gl_CACHE_VAL_SILENT(cache-id, command-to-set-it) 639# is like AC_CACHE_VAL(cache-id, command-to-set-it), except that it does not 640# output a spurious "(cached)" mark in the midst of other configure output. 641# This macro should be used instead of AC_CACHE_VAL when it is not surrounded 642# by an AC_MSG_CHECKING/AC_MSG_RESULT pair. 643AC_DEFUN([gl_CACHE_VAL_SILENT], 644[ 645 saved_as_echo_n="$as_echo_n" 646 as_echo_n=':' 647 AC_CACHE_VAL([$1], [$2]) 648 as_echo_n="$saved_as_echo_n" 649]) 650 651# AS_VAR_COPY was added in autoconf 2.63b 652m4_define_default([AS_VAR_COPY], 653[AS_LITERAL_IF([$1[]$2], [$1=$$2], [eval $1=\$$2])]) 654