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| author | Andy Wingo <wingo@pobox.com> | 2021-01-20 21:52:54 +0100 |
|---|---|---|
| committer | Andy Wingo <wingo@pobox.com> | 2021-01-20 23:03:56 +0100 |
| commit | a91b95cca2d397c84f8b9bbd602d40209a7092ce (patch) | |
| tree | 2c286a291f5a2b812d6e216be10936f2709d59cf /m4/stddef_h.m4 | |
| parent | 758b31994cff582c7e8785b4cc2240dbf3573837 (diff) | |
| download | guile-a91b95cca2d397c84f8b9bbd602d40209a7092ce.tar.gz | |
Update Gnulib to v0.1-4379-g2ef5a9b4b
Also bump required autoconf version to 2.64, as required by Gnulib.
Diffstat (limited to 'm4/stddef_h.m4')
| -rw-r--r-- | m4/stddef_h.m4 | 45 |
1 files changed, 39 insertions, 6 deletions
diff --git a/m4/stddef_h.m4 b/m4/stddef_h.m4 index f45def101..cd666c4a5 100644 --- a/m4/stddef_h.m4 +++ b/m4/stddef_h.m4 @@ -1,22 +1,54 @@ -dnl A placeholder for <stddef.h>, for platforms that have issues. -# stddef_h.m4 serial 5 -dnl Copyright (C) 2009-2017 Free Software Foundation, Inc. +# stddef_h.m4 serial 9 +dnl Copyright (C) 2009-2021 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. +dnl A placeholder for <stddef.h>, for platforms that have issues. + AC_DEFUN([gl_STDDEF_H], [ AC_REQUIRE([gl_STDDEF_H_DEFAULTS]) AC_REQUIRE([gt_TYPE_WCHAR_T]) + + dnl Persuade OpenBSD <stddef.h> to declare max_align_t. + AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + STDDEF_H= - AC_CHECK_TYPE([max_align_t], [], [HAVE_MAX_ALIGN_T=0; STDDEF_H=stddef.h], - [[#include <stddef.h> - ]]) + + dnl Test whether the type max_align_t exists and whether its alignment + dnl "is as great as is supported by the implementation in all contexts". + AC_CACHE_CHECK([for good max_align_t], + [gl_cv_type_max_align_t], + [AC_COMPILE_IFELSE( + [AC_LANG_PROGRAM( + [[#include <stddef.h> + unsigned int s = sizeof (max_align_t); + #if defined __GNUC__ || defined __clang__ || defined __IBM__ALIGNOF__ + int check1[2 * (__alignof__ (double) <= __alignof__ (max_align_t)) - 1]; + int check2[2 * (__alignof__ (long double) <= __alignof__ (max_align_t)) - 1]; + #endif + typedef struct { char a; max_align_t b; } max_helper; + typedef struct { char a; long b; } long_helper; + typedef struct { char a; double b; } double_helper; + typedef struct { char a; long double b; } long_double_helper; + int check3[2 * (offsetof (long_helper, b) <= offsetof (max_helper, b)) - 1]; + int check4[2 * (offsetof (double_helper, b) <= offsetof (max_helper, b)) - 1]; + int check5[2 * (offsetof (long_double_helper, b) <= offsetof (max_helper, b)) - 1]; + ]])], + [gl_cv_type_max_align_t=yes], + [gl_cv_type_max_align_t=no]) + ]) + if test $gl_cv_type_max_align_t = no; then + HAVE_MAX_ALIGN_T=0 + STDDEF_H=stddef.h + fi + if test $gt_cv_c_wchar_t = no; then HAVE_WCHAR_T=0 STDDEF_H=stddef.h fi + AC_CACHE_CHECK([whether NULL can be used in arbitrary expressions], [gl_cv_decl_null_works], [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stddef.h> @@ -28,6 +60,7 @@ AC_DEFUN([gl_STDDEF_H], REPLACE_NULL=1 STDDEF_H=stddef.h fi + AC_SUBST([STDDEF_H]) AM_CONDITIONAL([GL_GENERATE_STDDEF_H], [test -n "$STDDEF_H"]) if test -n "$STDDEF_H"; then |