match: make glob '**/' match the empty string Previously, a glob pattern of the form 'foo/**/bar' would match 'foo/a/bar' but not 'foo/bar'. That was because the '**' in 'foo/**/bar' would be translated to '.*', making the final regex pattern 'foo/.*/bar'. That pattern doesn't match the string 'foo/bar'. This is a bug because the '**/' glob matches the empty string in standard Unix shells like bash and zsh. Fix that by making the ending '/' optional if an empty string can be matched.