as: Reject unknown -gXXX option

	* as.c (parse_args): Reject unknown -gXXX option.
	* testsuite/gas/all/empty.s: New file.
	* testsuite/gas/all/pr29067.d: Likewise.
	* testsuite/gas/all/pr29067.err: Likewise.
	* testsuite/gas/all/gas.exp: Run pr29067.
5 files changed