Added type signature to fix GHC 6.8 problem reported by Jean-Philippe.

src/GF/UseGrammar/Transfer.hs

@@ -57,6 +57,7 @@ core2exp e = case e of
   T.EInteger i -> EInt $ fromInteger i
   T.EMeta _  -> uExp  -- meta symbol 0, refreshed by GF
  where
+   var :: T.CIdent -> Ident
    var (T.CIdent x) = zIdent x