| 1 | # environ.m4 serial 8
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| 2 | dnl Copyright (C) 2001-2004, 2006-2021 Free Software Foundation, Inc.
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| 3 | dnl This file is free software; the Free Software Foundation
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| 4 | dnl gives unlimited permission to copy and/or distribute it,
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| 5 | dnl with or without modifications, as long as this notice is preserved.
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| 6 |
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| 7 | AC_DEFUN_ONCE([gl_ENVIRON],
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| 8 | [
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| 9 | AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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| 10 | dnl Persuade glibc <unistd.h> to declare environ.
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| 11 | AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
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| 12 |
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| 13 | AC_CHECK_HEADERS_ONCE([unistd.h])
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| 14 | gt_CHECK_VAR_DECL(
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| 15 | [#if HAVE_UNISTD_H
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| 16 | #include <unistd.h>
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| 17 | #endif
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| 18 | /* mingw, BeOS, Haiku declare environ in <stdlib.h>, not in <unistd.h>. */
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| 19 | #include <stdlib.h>
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| 20 | ],
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| 21 | [environ])
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| 22 | if test $gt_cv_var_environ_declaration != yes; then
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| 23 | HAVE_DECL_ENVIRON=0
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| 24 | fi
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| 25 | ])
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| 26 |
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| 27 | # Check if a variable is properly declared.
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| 28 | # gt_CHECK_VAR_DECL(includes,variable)
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| 29 | AC_DEFUN([gt_CHECK_VAR_DECL],
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| 30 | [
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| 31 | define([gt_cv_var], [gt_cv_var_]$2[_declaration])
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| 32 | AC_CACHE_CHECK([if $2 is properly declared], [gt_cv_var],
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| 33 | [AC_COMPILE_IFELSE(
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| 34 | [AC_LANG_PROGRAM(
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| 35 | [[$1
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| 36 | typedef struct { int foo; } foo_t;
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| 37 | extern foo_t $2;]],
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| 38 | [[$2.foo = 1;]])],
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| 39 | [gt_cv_var=no],
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| 40 | [gt_cv_var=yes])])
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| 41 | if test $gt_cv_var = yes; then
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| 42 | AC_DEFINE([HAVE_]m4_translit($2, [a-z], [A-Z])[_DECL], 1,
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| 43 | [Define if you have the declaration of $2.])
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| 44 | fi
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| 45 | undefine([gt_cv_var])
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| 46 | ])
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