Changes to ghc

Changes to ghc:
commit b18bfda27a5caa10e899712ac2a1a5af778a8d52
Author: Jan Stolarek <jan.stolarek@p.lodz.pl>
Date:   Thu Jul 3 08:16:28 2014 +0200

    Update documentation

      * fix links to the User's Guide in ghc and ghci --help messages
      * fix default stack size info in RTS help message

    (cherry picked from commit 311c55d132a65e657771e5f58b12a205e0a4af99)