patch applied (ghc): MERGE: In hashExpr, use Word32 rather than relying on wrapping behaviour of Int

[Ian Lynagh]

Sun Dec  3 14:33:37 PST 2006  Ian Lynagh <igloo at earth.li>
  * MERGE: In hashExpr, use Word32 rather than relying on wrapping behaviour of Int
  Fixes #952, as it turns out.
  
  When compiling via C, we are at the mercy of C's undefined behaviour
  with respect to overflow of signed integer operations, and this was
  biting us here.
  
  Perhaps we should always add the -fwrapv flag to gcc, but since
  Haskell doesn't define overflow on Int either, it seemed the right
  thing to do to fix this code anyway.

    M ./compiler/coreSyn/CoreUtils.lhs -12 +18