Changes to ghc

Changes to ghc:
commit 7561e37103041d6691c70683f910cdb97952483a
Author: Herbert Valerio Riedel <hvr@gnu.org>
Date:   Sun Feb 9 14:59:49 2014 +0100

    double-negate test for Stage1Only to fix `make clean`

    This was causing `utils/ghctags/dist-install` to not get removed
    on `make clean` as `Stage1Only` was unset. So testing for `!= YES` is
    less fragile than testing for `== NO` in this case.

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