-# alloca.m4 serial 1
-dnl Copyright (C) 2002 Free Software Foundation, Inc.
-dnl This file is free software, distributed under the terms of the GNU
-dnl General Public License. As a special exception to the GNU General
-dnl Public License, this file may be distributed as part of a program
-dnl that contains a configuration script generated by Autoconf, under
-dnl the same distribution terms as the rest of that program.
+# alloca.m4 serial 10
+dnl Copyright (C) 2002-2004, 2006-2007, 2009-2011 Free Software Foundation,
+dnl 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_FUNC_ALLOCA],
[
if test $ac_cv_func_alloca_works = no; then
gl_PREREQ_ALLOCA
fi
+
+ # Define an additional variable used in the Makefile substitution.
+ if test $ac_cv_working_alloca_h = yes; then
+ AC_CACHE_CHECK([for alloca as a compiler built-in], [gl_cv_rpl_alloca], [
+ AC_EGREP_CPP([Need own alloca], [
+#if defined __GNUC__ || defined _AIX || defined _MSC_VER
+ Need own alloca
+#endif
+ ], [gl_cv_rpl_alloca=yes], [gl_cv_rpl_alloca=no])
+ ])
+ if test $gl_cv_rpl_alloca = yes; then
+ dnl OK, alloca can be implemented through a compiler built-in.
+ AC_DEFINE([HAVE_ALLOCA], [1],
+ [Define to 1 if you have 'alloca' after including <alloca.h>,
+ a header that may be supplied by this distribution.])
+ ALLOCA_H=alloca.h
+ else
+ dnl alloca exists as a library function, i.e. it is slow and probably
+ dnl a memory leak. Don't define HAVE_ALLOCA in this case.
+ ALLOCA_H=
+ fi
+ else
+ ALLOCA_H=alloca.h
+ fi
+ AC_SUBST([ALLOCA_H])
])
# Prerequisites of lib/alloca.c.
# STACK_DIRECTION is already handled by AC_FUNC_ALLOCA.
-AC_DEFUN([gl_PREREQ_ALLOCA], [
- AC_CHECK_HEADERS_ONCE(stdlib.h string.h)
-])
+AC_DEFUN([gl_PREREQ_ALLOCA], [:])