Pragmas for FFI imports

[Einar Karttunen]

Hello

I would like to propose two pragmas to be included in Haskell'
for use with FFI. One for specifying the include file defining
the foreign import (INCLUDE in ghc) and an another for defining
a library that the foreign import depends on, called FFI_LIB
(not implemented at the moment). These changes would not break
any existing code.

- Einar Karttunen