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73 lines
2.3 KiB
Plaintext
73 lines
2.3 KiB
Plaintext
dnl A placeholder for <stddef.h>, for platforms that have issues.
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# stddef_h.m4 serial 6
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dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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AC_DEFUN([gl_STDDEF_H],
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[
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AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
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AC_REQUIRE([gt_TYPE_WCHAR_T])
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STDDEF_H=
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dnl Test whether the type max_align_t exists and whether its alignment
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dnl "is as great as is supported by the implementation in all contexts".
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AC_CACHE_CHECK([for good max_align_t],
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[gl_cv_type_max_align_t],
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[AC_COMPILE_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <stddef.h>
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unsigned int s = sizeof (max_align_t);
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#if defined __GNUC__ || defined __IBM__ALIGNOF__
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int check1[2 * (__alignof__ (double) <= __alignof__ (max_align_t)) - 1];
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int check2[2 * (__alignof__ (long double) <= __alignof__ (max_align_t)) - 1];
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#endif
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]])],
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[gl_cv_type_max_align_t=yes],
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[gl_cv_type_max_align_t=no])
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])
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if test $gl_cv_type_max_align_t = no; then
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HAVE_MAX_ALIGN_T=0
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STDDEF_H=stddef.h
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fi
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if test $gt_cv_c_wchar_t = no; then
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HAVE_WCHAR_T=0
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STDDEF_H=stddef.h
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fi
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AC_CACHE_CHECK([whether NULL can be used in arbitrary expressions],
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[gl_cv_decl_null_works],
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[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stddef.h>
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int test[2 * (sizeof NULL == sizeof (void *)) -1];
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]])],
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[gl_cv_decl_null_works=yes],
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[gl_cv_decl_null_works=no])])
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if test $gl_cv_decl_null_works = no; then
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REPLACE_NULL=1
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STDDEF_H=stddef.h
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fi
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AC_SUBST([STDDEF_H])
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AM_CONDITIONAL([GL_GENERATE_STDDEF_H], [test -n "$STDDEF_H"])
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if test -n "$STDDEF_H"; then
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gl_NEXT_HEADERS([stddef.h])
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fi
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])
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AC_DEFUN([gl_STDDEF_MODULE_INDICATOR],
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[
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dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
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AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
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gl_MODULE_INDICATOR_SET_VARIABLE([$1])
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])
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AC_DEFUN([gl_STDDEF_H_DEFAULTS],
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[
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dnl Assume proper GNU behavior unless another module says otherwise.
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REPLACE_NULL=0; AC_SUBST([REPLACE_NULL])
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HAVE_MAX_ALIGN_T=1; AC_SUBST([HAVE_MAX_ALIGN_T])
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HAVE_WCHAR_T=1; AC_SUBST([HAVE_WCHAR_T])
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])
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