Add support for an Autotest test suite for Bison.

* m4/m4.m4, m4/atconfig.m4: New files.
* m4/Makefile.am (EXTRA_DIST): Adjust.
* tests/suite.m4, tests/Makefile.am, tests/atgeneral.m4: New
files.
* src/getargs.c: Display a more standard --version message.
* src/reader.c (reader): Formatting changes.
No longer depend upon VERSION_STRING.
* configure.in: No longer use `dnl'.
Set up the test suite and the new directory `tests/.
(VERSION_STRING): Remove.

tests/Makefile.am

@@ -0,0 +1,40 @@
+## Process this file with automake to create Makefile.in.
+
+## Makefile for Bison testsuite.
+## Copyright (C) 2000 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, 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., 59 Temple Place - Suite 330, Boston, MA
+## 02111-1307, USA.
+
+# Distribute the testsuite since GNU M4 is needed to build it.
+noinst_SCRIPTS = testsuite
+
+SUITE =
+
+EXTRA_DIST = atgeneral.m4 suite.m4 $(SUITE)
+
+check-local: atconfig testsuite
+	$(SHELL) testsuite
+
+testsuite: atgeneral.m4 suite.m4 $(SUITE)
+	$(M4) -I $(srcdir) atgeneral.m4 suite.m4 | \
+          sed -e 's/[ 	]*$$//' | \
+	  sed -e '/^$$/N;/\n$$/D' > $@-tmp
+	chmod +x $@-tmp
+	mv $@-tmp $@
+
+CLEANFILES = debug-*.sh
+DISTCLEANFILES = atconfig
+MAINTAINERCLEANFILES = testsuite