Changing the `Binary` instance for `Double` and `Float`

elaforge:

was supposed to replace binary for ghc’s internal use. While the latter seems to have never happened

I think ghc only uses the binary package for the package db at this point. Most internal uses use GHC’s own Binary class:

class Binary a where
  put\_   :: WriteBinHandle -> a -> IO ()
  put    :: WriteBinHandle -> a -> IO (Bin a)
  get    :: ReadBinHandle -> IO a

But while that works for GHC I wouldn’t recommend this interface for a library.