patch applied (ghc-6.8/ghc): Add and use seqBitmap when constructing SRTs

[Ian Lynagh]

Wed Feb 27 06:45:05 PST 2008  Ian Lynagh <igloo at earth.li>
  * Add and use seqBitmap when constructing SRTs
  This roughly halves memory usage when compiling
      module Foo where
  
      foo :: Double -> Int
      foo x | x == 1 = 1
      ...
      foo x | x == 500 = 500
  without optimisation.

    M ./compiler/codeGen/Bitmap.hs -1 +6
    M ./compiler/simplStg/SRT.lhs -2 +2