Changes to ghc(2)

Changes to ghc:
commit 78afa2078e474c9e8fd3d0f347c5652f296d5248
Author: Jan Stolarek <jan.stolarek@p.lodz.pl>
Date:   Sat Feb 1 19:15:06 2014 +0100

    Nuke dead code

      * CmmRewriteAddignments module was replaced by CmmSink a long
        time ago. That module is now available at
        https://ghc.haskell.org/trac/ghc/wiki/Commentary/Compiler/Hoopl/Examples
        wiki page.

      * removeDeadAssignments function was not used and it was also
        moved to the above page.

      * I also nuked some commented out debugging code that was not
        used for 1,5 year.

commit 99c3ed81ac53629771b00a0abbe37c989ea45cd6
Author: Jan Stolarek <jan.stolarek@p.lodz.pl>
Date:   Sat Feb 1 18:00:48 2014 +0100

    Simplify Control Flow Optimisations Cmm pass

    It turns out that one of the cases in the optimization pass was
    a special case of another. I remove that specialization since it
    does not have impact on compilation time, and the resulting Cmm
    is identical.