-# environ.m4 serial 2
-dnl Copyright (C) 2001-2004, 2006-2009 Free Software Foundation, Inc.
+# environ.m4 serial 3
+dnl Copyright (C) 2001-2004, 2006-2010 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([gl_ENVIRON],
+AC_DEFUN_ONCE([gl_ENVIRON],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
dnl Persuade glibc <unistd.h> to declare environ.