* bootstrap (gnulib_modules): Add strverscmp.

* lib/.cvsignore: Add strverscmp.c, strverscmp.h.
* m4/.cvsignore: Add strverscmp.m4.
* src/parse-gram.y (%require): New token, new rule.
(version_check): New.
* src/scan-gram.l (%require): Adjust.
* tests/input.at (AT_REQUIRE): New.
Use it.
* doc/bison.texinfo (Require Decl): New.
(Calc++ Parser): Use %require.

m4/.cvsignore

@@ -30,6 +30,7 @@ strndup.m4
 strnlen.m4
 strtol.m4
 strtoul.m4
+strverscmp.m4
 unistd-safer.m4
 unlocked-io.m4
 xalloc.m4