convert hacky shell linux mklibs code to haskell ; fixing symlink bug

The shell code was nasty, and buggy. New haskell code is much nicer,
and it's easy to do complicated calculations to properly convert possibly
absolute symlinks between libraries into relative links using it.

Utility/Directory.hs

@@ -37,7 +37,7 @@ dirContents d = map (d </>) . filter (not . dirCruft) <$> getDirectoryContents d
 {- Gets files in a directory, and then its subdirectories, recursively,
  - and lazily.
  -
- - Follows symlinks to other subdirectories.
+ - Does not follow symlinks to other subdirectories.
  -
  - When the directory does not exist, no exception is thrown,
  - instead, [] is returned. -}