Automatically generate Storable instances for enums

[poscat0x04]

Enums are CInts in memory so this should work for all types

instance Storable SomeType where
    sizeOf _ = 4
    alignment _ = 4
    peek ptr = do
        val <- peek (castPtr ptr)
        return $ toEnum $ fromEnum (val :: CInt)
    poke ptr v = poke (castPtr ptr) (toEnum $ fromEnum v :: CInt)

It would be nice if we add syntactic sugar for automatically generating storables instances.