patch applied (ghc): Support for using libffi to implement FFI calls in GHCi (#631)

[Simon Marlow]

Mon Feb  4 08:10:53 PST 2008  Simon Marlow <simonmar at microsoft.com>
  * Support for using libffi to implement FFI calls in GHCi (#631)
  This means that an unregisterised build on a platform not directly
  supported by GHC can now have full FFI support using libffi.
  
  Also in this commit:
  
   - use PrimRep rather than CgRep to describe FFI args in the byte
     code generator.  No functional changes, but PrimRep is more correct.
  
   - change TyCon.sizeofPrimRep to primRepSizeW, which is more useful

    M ./compiler/Makefile +5
    M ./compiler/ghci/ByteCodeAsm.lhs -1 +2
    M ./compiler/ghci/ByteCodeFFI.lhs -45 +63
    M ./compiler/ghci/ByteCodeGen.lhs -38 +57
    M ./compiler/ghci/ByteCodeInstr.lhs -1 +1
    A ./compiler/ghci/LibFFI.hsc
    M ./compiler/ghci/RtClosureInspect.hs -4 +3
    M ./compiler/types/TyCon.lhs -13 +16
    M ./rts/Interpreter.c -22 +72