if strings.Contains(stderr, "unrecognized command line option") {
		// We're using an old version of GCC that doesn't understand
		// -fdiagnostics-color. Those versions can't print color anyway,
		// so just rerun without that option.
		stderr = p.gccErrors(b.Bytes())
	}
	if stderr == "" {
		fatalf("%s produced no output\non input:\n%s", gccBaseCmd[0], b.Bytes())
	}

	completed := false