1
0
mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-12-20 10:23:57 +00:00
emacs/m4/environ.m4
Paul Eggert 220a9ecba1 Merge from Gnulib
This incorporates:
2018-01-01 maint: Run 'make update-copyright'
2017-12-29 Add cross-compilation results for GNU/Hurd.
2017-12-12 explicit_bzero: port to macOS + Clang 9.0.0
2017-12-31 17:21:33 -08:00

48 lines
1.4 KiB
Plaintext

# environ.m4 serial 6
dnl Copyright (C) 2001-2004, 2006-2018 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_MSG_CHECKING([if $2 is properly declared])
AC_CACHE_VAL([gt_cv_var], [
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[$1
extern struct { int foo; } $2;]],
[[$2.foo = 1;]])],
[gt_cv_var=no],
[gt_cv_var=yes])])
AC_MSG_RESULT([$gt_cv_var])
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])
])