Merge in new code generator branch.
This changes the new code generator to make use of the Hoopl package for dataflow analysis. Hoopl is a new boot package, and is maintained in a separate upstream git repository (as usual, GHC has its own lagging darcs mirror in http://darcs.haskell.org/packages/hoopl). During this merge I squashed recent history into one patch. I tried to rebase, but the history had some internal conflicts of its own which made rebase extremely confusing, so I gave up. The history I squashed was: - Update new codegen to work with latest Hoopl - Add some notes on new code gen to cmm-notes - Enable Hoopl lag package. - Add SPJ note to cmm-notes - Improve GC calls on new code generator. Work in this branch was done by: - Milan Straka <firstname.lastname@example.org> - John Dias <email@example.com> - David Terei <firstname.lastname@example.org> Edward Z. Yang <email@example.com> merged in further changes from GHC HEAD and fixed a few bugs.