Changes to ghc

Changes to ghc:
commit 115eb4a8dba371dd155795910dc52c0e33389599
Author: Herbert Valerio Riedel <hvr@gnu.org>
Date:   Fri Oct 25 15:00:06 2013 +0200

    Clean `.buildinfo` only if `.buildinfo.in` exists

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