patch applied (ghc): Add -fsimplifier-phases option

[Roman Leshchinskiy]

Tue Jan  8 18:24:49 PST 2008  Roman Leshchinskiy <rl at cse.unsw.edu.au>
  * Add -fsimplifier-phases option
  
  It controls the number of simplifier phases run during optimisation. These are
  numbered from n to 1 (by default, n=2). Phase 0 is always run regardless of
  this flag. The flag is ignored with -O0 since (practically) no optimisation is
  performed in that case.

    M ./compiler/main/DynFlags.hs -11 +20