Actually check version for bison.

Clean up oniguruma checks.

m4/ax_prog_bison_version.m4

@@ -0,0 +1,68 @@
+# ===========================================================================
+#   Modified from
+#   http://www.gnu.org/software/autoconf-archive/ax_prog_perl_version.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_PROG_BISON_VERSION([VERSION],[ACTION-IF-TRUE],[ACTION-IF-FALSE])
+#
+# DESCRIPTION
+#
+#   Makes sure that bison supports the version indicated. If true the shell
+#   commands in ACTION-IF-TRUE are executed. If not the shell commands in
+#   ACTION-IF-FALSE are run. Note if $PERL is not set the macro will fail.
+#
+#   Example:
+#
+#     AC_PROG_YACC
+#     AX_PROG_BISON_VERSION([3.0.0],[ ... ],[ ... ])
+#
+#   This will check to make sure that the bison you have supports at least
+#   version 3.0.0.
+#
+#   NOTE: This macro uses the $YACC variable to perform the check.
+#   AX_WITH_YACC can be used to set that variable prior to running this
+#   macro. The $BISON_VERSION variable will be set with the detected
+#   version.
+#
+# LICENSE
+#
+#   Copyright (c) 2009 Francesco Salvestrini <salvestrini@users.sourceforge.net>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 12
+
+AC_DEFUN([AX_PROG_BISON_VERSION],[
+    AC_REQUIRE([AC_PROG_SED])
+    AC_REQUIRE([AC_PROG_GREP])
+
+    AS_IF([test -n "$YACC"],[
+        ax_bison_version="$1"
+
+        AC_MSG_CHECKING([for bison version])
+        changequote(<<,>>)
+        bison_version=`$YACC --version 2>&1 \
+          | $GREP bison \
+          | $SED -rn -e 's/bison .* ([0-9]+([.][0-9])+)+/\1/p'`
+        changequote([,])
+        AC_MSG_RESULT($bison_version)
+
+	AC_SUBST([BISON_VERSION],[$bison_version])
+
+        AX_COMPARE_VERSION([$ax_bison_version],[le],[$bison_version],[
+	    :
+            $2
+        ],[
+	    :
+            $3
+        ])
+    ],[
+        AC_MSG_WARN([could not find bison])
+        $3
+    ])
+])