Proposal: add Data.Data instances for Foreign.C.Types

I recently was wanting to use SYB for an AST datatype which includes constants like CDouble/CFloat. Currently Data.Data exports Int8...Int64 and Word instances, but no instances for Foreign.C.Types: http://www.haskell.org/ghc/docs/latest/html/libraries/base/Data-Data.html Is there any reason these instances should not be exported by Data.Data? The proposal here is simply to add them. It's just a matter of copy-pasting the existing instances and I can provide the patch. -Ryan