Work around missing type signature in Happy

Happy generates

      notHappyAtAll = error "Blah"

without a type signature, and currently the new
typechecker doesn't generalise it.  This patch
says "no monomorphism restriction" which makes it
generalise again.

Better would be to add a type sig to Happy's template

HpcParser.y

 { 
-{-# OPTIONS -Wwarn #-}
+{-# OPTIONS -Wwarn -XNoMonomorphismRestriction #-}
+-- The NoMonomorphismRestriction deals with a Happy infelicity
+--    With OutsideIn's more conservativ monomorphism restriction
+--    we aren't generalising
+--        notHappyAtAll = error "urk"
+--    which is terrible.  Switching off the restriction allows
+--    the generalisation.  Better would be to make Happy generate
+--    an appropriate signature.
+--
 -- The above warning supression flag is a temporary kludge.
 -- While working on this module you are encouraged to remove it and fix
 -- any warnings in the module. See