Changes to ghc

Changes to ghc:
commit ec550e8f951e50fb91c89389e2e77a3358079c3a
Author: Herbert Valerio Riedel <hvr@gnu.org>
Date:   Tue Jun 24 22:58:41 2014 +0200

    Fixup c1035d51e to behave more like in GHC 7.6

    The fix in c1035d51e (addressing #9231) was done under the assumption
    that `Data.Fixed` is used only with power-of-10 `resolution`. This
    follow-up fixup changes the behavior to be more consistent with the
    previous behavior in GHC 7.6

    For instance, for the following `B7` resolution

       > data B7
       > instance HasResolution B7 where resolution _ = 128

    After this patch, the following behavior is now observable:

       > 1.070 :: Fixed B7
       1.062
       > 1.062 :: Fixed B7
       1.054

       > read "1.070" :: Fixed B7
       1.062
       > read "1.062" :: Fixed B7
       1.054

    This doesn't provide the desirable "read . show == id" property
    yet (which didn't hold in GHC 7.6 either), but at least `fromRational`
    and `read` are consistent.

    Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>