[jhc] building transformers library, irrefutable patterns

Hello I can build all of transformers (http://hackage.haskell.org/package/transformers) but only when excluding the files: Control.Monad.Trans.RWS.Lazy, Control.Monad.Trans.State.Lazy, Control.Monad.Trans.Writer.Lazy Which use irrefutable patterns, I could probably make this work without them but I just thought it was worth mentioning.