1# environ.m4 serial 8 2dnl Copyright (C) 2001-2004, 2006-2022 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_DEFUN_ONCE([gl_ENVIRON], 8[ 9 AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) 10 dnl Persuade glibc <unistd.h> to declare environ. 11 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) 12 13 AC_CHECK_HEADERS_ONCE([unistd.h]) 14 gt_CHECK_VAR_DECL( 15 [#if HAVE_UNISTD_H 16 #include <unistd.h> 17 #endif 18 /* mingw, BeOS, Haiku declare environ in <stdlib.h>, not in <unistd.h>. */ 19 #include <stdlib.h> 20 ], 21 [environ]) 22 if test $gt_cv_var_environ_declaration != yes; then 23 HAVE_DECL_ENVIRON=0 24 fi 25]) 26 27# Check if a variable is properly declared. 28# gt_CHECK_VAR_DECL(includes,variable) 29AC_DEFUN([gt_CHECK_VAR_DECL], 30[ 31 define([gt_cv_var], [gt_cv_var_]$2[_declaration]) 32 AC_CACHE_CHECK([if $2 is properly declared], [gt_cv_var], 33 [AC_COMPILE_IFELSE( 34 [AC_LANG_PROGRAM( 35 [[$1 36 typedef struct { int foo; } foo_t; 37 extern foo_t $2;]], 38 [[$2.foo = 1;]])], 39 [gt_cv_var=no], 40 [gt_cv_var=yes])]) 41 if test $gt_cv_var = yes; then 42 AC_DEFINE([HAVE_]m4_translit($2, [a-z], [A-Z])[_DECL], 1, 43 [Define if you have the declaration of $2.]) 44 fi 45 undefine([gt_cv_var]) 46]) 47