Log Message:
Update ghc to 6.2.1.

There are too many changes compared to version 5.04.3 to list here...
The changes are described in:
  http://www.haskell.org/ghc/docs/6.0.1/html/users_guide/release-6-0.html
  http://www.haskell.org/ghc/docs/6.2.1/html/users_guide/release-6-2.html