* m4/c-working.m4: New file.

* configure.ac (BISON_TEST_FOR_WORKING_C_COMPILER): Use it.

m4/c-working.m4

@@ -0,0 +1,29 @@
+# Sanity test a C compiler.
+
+# Copyright (C) 2006 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301  USA
+
+# Written by Paul Eggert.
+
+AC_DEFUN([BISON_TEST_FOR_WORKING_C_COMPILER], [
+  AC_COMPILE_IFELSE(
+    [AC_LANG_PROGRAM(
+       [[#include <limits.h>
+	 int test_array[CHAR_BIT];]])],
+    [],
+    [AC_MSG_FAILURE([cannot compile a simple C program])])
+])