Changes to ghc

Changes to ghc:
commit 20a25b56c5cbc83add6b9611706363109edbfbc2
Author: Edward Z. Yang <ezyang@cs.stanford.edu>
Date:   Wed Jan 15 13:29:53 2014 -0800

    PLT Redex definition of an STG-like language, as-per the fast curry paper.

    Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>