-# alloca.m4 serial 7
-dnl Copyright (C) 2002-2004, 2006 Free Software Foundation, Inc.
+# alloca.m4 serial 9
+dnl Copyright (C) 2002-2004, 2006-2007, 2009-2010 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.
# Define an additional variable used in the Makefile substitution.
if test $ac_cv_working_alloca_h = yes; then
- AC_CACHE_CHECK([whether alloca must be replaced], [gl_cv_rpl_alloca], [
+ 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
+ Need own alloca
#endif
- ], [gl_cv_rpl_alloca=yes], [gl_cv_rpl_alloca=no])
+ ], [gl_cv_rpl_alloca=yes], [gl_cv_rpl_alloca=no])
])
if test $gl_cv_rpl_alloca = yes; then
- 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.])
+ 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])
-
- AC_DEFINE(HAVE_ALLOCA_H, 1,
- [Define HAVE_ALLOCA_H for backward compatibility with older code
- that includes <alloca.h> only if HAVE_ALLOCA_H is defined.])
])
# Prerequisites of lib/alloca.c.