| # environ.m4 serial 7 |
| dnl Copyright (C) 2001-2004, 2006-2019 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. |
| |
| AC_DEFUN_ONCE([gl_ENVIRON], |
| [ |
| AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) |
| dnl Persuade glibc <unistd.h> to declare environ. |
| AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) |
| |
| AC_CHECK_HEADERS_ONCE([unistd.h]) |
| gt_CHECK_VAR_DECL( |
| [#if HAVE_UNISTD_H |
| #include <unistd.h> |
| #endif |
| /* mingw, BeOS, Haiku declare environ in <stdlib.h>, not in <unistd.h>. */ |
| #include <stdlib.h> |
| ], |
| [environ]) |
| if test $gt_cv_var_environ_declaration != yes; then |
| HAVE_DECL_ENVIRON=0 |
| fi |
| ]) |
| |
| # Check if a variable is properly declared. |
| # gt_CHECK_VAR_DECL(includes,variable) |
| AC_DEFUN([gt_CHECK_VAR_DECL], |
| [ |
| define([gt_cv_var], [gt_cv_var_]$2[_declaration]) |
| AC_CACHE_CHECK([if $2 is properly declared], [gt_cv_var], |
| [AC_COMPILE_IFELSE( |
| [AC_LANG_PROGRAM( |
| [[$1 |
| extern struct { int foo; } $2;]], |
| [[$2.foo = 1;]])], |
| [gt_cv_var=no], |
| [gt_cv_var=yes])]) |
| if test $gt_cv_var = yes; then |
| AC_DEFINE([HAVE_]m4_translit($2, [a-z], [A-Z])[_DECL], 1, |
| [Define if you have the declaration of $2.]) |
| fi |
| undefine([gt_cv_var]) |
| ]) |