-- | A 'FilePattern' that will only match 'isRelativePath' values.
isRelativePattern :: FilePattern -> Bool
isRelativePattern ('*':'*':xs)
    | [] <- xs = True
    | x:_ <- xs, isPathSeparator x = True
isRelativePattern :: FilePattern -> Bool
isRelativePattern ('*':'*':xs)
    | [] <- xs = True
    | x:_ <- xs, isPathSeparator x = True
isRelativePattern ('*':'*':xs)
    | [] <- xs = True
    | x:_ <- xs, isPathSeparator x = True