patch applied (packages/base): add foldr/build optimisation for take and replicate

[Simon Marlow]

Thu Jan 26 08:46:03 PST 2006  Simon Marlow <simonmar at microsoft.com>
  * add foldr/build optimisation for take and replicate
  This allows take to be deforested, and improves performance of
  replicate and replicateM/replicateM_.  We have a separate problem that
  means expressions involving [n..m] aren't being completely optimised
  because eftIntFB isn't being inlined but otherwise the results look
  good.  
  
  Sadly this has invalidated a number of the nofib benchmarks which were
  erroneously using take to duplicate work in a misguided attempt to
  lengthen their runtimes (ToDo).

    M ./GHC/List.lhs +18