patch applied (ghc): Fix free-variable finder

[Simon Peyton Jones]

Thu Mar  2 09:52:47 PST 2006  simonpj at microsoft.com
  * Fix free-variable finder
  
  After a long hunt I discovered that the reason that GHC.Enum.eftIntFB
  was being marked as a loop-breaker was the bizare behaviour of exprFreeVars,
  which returned not only the free variables of an expression but also the
  free variables of RULES attached to variables occuring in the expression!
  
  This was clearly deliberate (the comment was CoreFVs rev 1.1 in 1999) but
  I've removed it; I've left the comment with further notes in case there
  turns out to be a Deep Reason.
  
  

    M ./ghc/compiler/coreSyn/CoreFVs.lhs -16 +38