* automake.in (parse_arguments): Diagnose empty arguments, options with missing argument, and support `--'. * aclocal.in (parse_arguments): Diagnose options with missing argument. * tests/aclocal.test: More checks. * tests/automake.test: New file. * tests/postprog.test: Use `--' for fun. * tests/Makefile.am (TESTS): Add automake.test. Report from Eric Blake.