patch applied (ghc): Improve error message (idea in Trac #3805)

[Simon Peyton Jones]

Tue Jan  5 01:55:32 PST 2010  simonpj at microsoft.com
  * Improve error message (idea in Trac #3805)
  Ignore-this: 109f041bb2a3be3beafc536aa5b8d9f
  
  If we see
  
     foreign export ccall foo :: ...blah...
  
  we now use the "foreign" to suggest -XForeignFunctionInterface

    M ./compiler/parser/RdrHsSyn.lhs -1 +13

View patch online:
http://darcs.haskell.org/ghc/_darcs/patches/20100105095532-1287e-15c189b3bb2c4768dc64d749ebdcc0b8f4ac2935.gz