Changes to ghc

Changes to ghc:
commit a2269bf81c8e95ad9a1bc3c32e425fdba7c3686a
Author: Krzysztof Gogolewski <krz.gogolewski@gmail.com>
Date:   Sat Feb 1 14:03:34 2014 +0100

    Remove some references to deprecated -fglasgow-exts in user's guide