Changes to ghc

Changes to ghc:
commit df2dd64dca0796f01356f5fb2ec41edf9762c349
Author: Edsko de Vries <edsko@well-typed.com>
Date:   Tue Dec 17 17:28:44 2013 +0000

    Add hook for splicing in renamer

    With the recent modifications to the TH infrastructure, many splices are now
    expanded in the renamer rather than the typechecker. This means that tools
    which inspect the renamed tree don't get to see the original splices. Added a
    new hook which gets called before such a splice gets expanded, analogous to the
    runQuasiQuoteHook.