func GlobLiteralPrefix(pattern string) string {
	pattern = clean(pattern)
	idx := globRegex.FindStringIndex(pattern)
	if idx == nil {
		return pattern
	}
	return pattern[:idx[0]]
}
func GlobLiteralPrefix(pattern string) string {
	pattern = clean(pattern)
	idx := globRegex.FindStringIndex(pattern)
	if idx == nil {
		return pattern
	}
	return pattern[:idx[0]]
}
// GlobLiteralPrefix returns the prefix before the first glob character