-# alloca.m4 serial 2
-dnl Copyright (C) 2002-2003 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 14
+dnl Copyright (C) 2002-2004, 2006-2007, 2009-2013 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],
[
fi
# Define an additional variable used in the Makefile substitution.
-
- AC_EGREP_CPP([Need own alloca], [
-#if defined __GNUC__ || defined _MSC_VER || !HAVE_ALLOCA_H
- Need own alloca
+ 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
- ],
- ALLOCA_H=alloca.h,
- ALLOCA_H=)
+ ], [gl_cv_rpl_alloca=yes], [gl_cv_rpl_alloca=no])
+ ])
+ if test $gl_cv_rpl_alloca = yes; then
+ dnl OK, alloca can be implemented through a compiler built-in.
+ AC_DEFINE([HAVE_ALLOCA], [1],
+ [Define to 1 if you have 'alloca' after including <alloca.h>,
+ a header that may be supplied by this distribution.])
+ ALLOCA_H=alloca.h
+ else
+ dnl alloca exists as a library function, i.e. it is slow and probably
+ dnl a memory leak. Don't define HAVE_ALLOCA in this case.
+ ALLOCA_H=
+ fi
+ else
+ ALLOCA_H=alloca.h
+ fi
AC_SUBST([ALLOCA_H])
+ AM_CONDITIONAL([GL_GENERATE_ALLOCA_H], [test -n "$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], [:])
+
+# This works around a bug in autoconf <= 2.68.
+# See <http://lists.gnu.org/archive/html/bug-gnulib/2011-06/msg00277.html>.
+
+m4_version_prereq([2.69], [] ,[
+
+# This is taken from the following Autoconf patch:
+# http://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=6cd9f12520b0d6f76d3230d7565feba1ecf29497
+
+# _AC_LIBOBJ_ALLOCA
+# -----------------
+# Set up the LIBOBJ replacement of 'alloca'. Well, not exactly
+# AC_LIBOBJ since we actually set the output variable 'ALLOCA'.
+# Nevertheless, for Automake, AC_LIBSOURCES it.
+m4_define([_AC_LIBOBJ_ALLOCA],
+[# The SVR3 libPW and SVR4 libucb both contain incompatible functions
+# that cause trouble. Some versions do not even contain alloca or
+# contain a buggy version. If you still want to use their alloca,
+# use ar to extract alloca.o from them instead of compiling alloca.c.
+AC_LIBSOURCES(alloca.c)
+AC_SUBST([ALLOCA], [\${LIBOBJDIR}alloca.$ac_objext])dnl
+AC_DEFINE(C_ALLOCA, 1, [Define to 1 if using 'alloca.c'.])
+
+AC_CACHE_CHECK(whether 'alloca.c' needs Cray hooks, ac_cv_os_cray,
+[AC_EGREP_CPP(webecray,
+[#if defined CRAY && ! defined CRAY2
+webecray
+#else
+wenotbecray
+#endif
+], ac_cv_os_cray=yes, ac_cv_os_cray=no)])
+if test $ac_cv_os_cray = yes; then
+ for ac_func in _getb67 GETB67 getb67; do
+ AC_CHECK_FUNC($ac_func,
+ [AC_DEFINE_UNQUOTED(CRAY_STACKSEG_END, $ac_func,
+ [Define to one of '_getb67', 'GETB67',
+ 'getb67' for Cray-2 and Cray-YMP
+ systems. This function is required for
+ 'alloca.c' support on those systems.])
+ break])
+ done
+fi
+
+AC_CACHE_CHECK([stack direction for C alloca],
+ [ac_cv_c_stack_direction],
+[AC_RUN_IFELSE([AC_LANG_SOURCE(
+[AC_INCLUDES_DEFAULT
+int
+find_stack_direction (int *addr, int depth)
+{
+ int dir, dummy = 0;
+ if (! addr)
+ addr = &dummy;
+ *addr = addr < &dummy ? 1 : addr == &dummy ? 0 : -1;
+ dir = depth ? find_stack_direction (addr, depth - 1) : 0;
+ return dir + dummy;
+}
+
+int
+main (int argc, char **argv)
+{
+ return find_stack_direction (0, argc + !argv + 20) < 0;
+}])],
+ [ac_cv_c_stack_direction=1],
+ [ac_cv_c_stack_direction=-1],
+ [ac_cv_c_stack_direction=0])])
+AH_VERBATIM([STACK_DIRECTION],
+[/* If using the C implementation of alloca, define if you know the
+ direction of stack growth for your system; otherwise it will be
+ automatically deduced at runtime.
+ STACK_DIRECTION > 0 => grows toward higher addresses
+ STACK_DIRECTION < 0 => grows toward lower addresses
+ STACK_DIRECTION = 0 => direction of growth unknown */
+@%:@undef STACK_DIRECTION])dnl
+AC_DEFINE_UNQUOTED(STACK_DIRECTION, $ac_cv_c_stack_direction)
+])# _AC_LIBOBJ_ALLOCA
])
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