Changes to ghc

Changes to ghc:
commit fb74d71756042fe954b2a82d208041df56a08377
Author: Dr. ERDI Gergo <gergo@erdi.hu>
Date:   Tue May 27 21:48:42 2014 +0800

    Assert that matcher-derived PatSyn types match the (redundant) stored types in IfacePatSyn