patch applied (ghc): Add -dasm-lint

[Ben Lippmeier]

Mon Sep 17 04:30:24 PDT 2007  Ben.Lippmeier at anu.edu.au
  * Add -dasm-lint
  
  When -dasm-lint is turned on the register conflict graph is checked for 
  internal consistency after each build/color pass. Make sure that all 
  edges point to valid nodes, that nodes are colored differently to their
  neighbours, and if the graph is supposed to be colored, that all nodes
  actually have a color.

    M ./compiler/main/DynFlags.hs +2
    M ./compiler/nativeGen/RegAllocColor.hs -4 +20
    M ./compiler/utils/GraphOps.hs -18 +64