Perl 4's special variable $* controls multi-line matching; it's been
  deprecated from Perl 5's inception, and is finally removed in Perl
  versions 5.9 (soon to be 5.10).

  Since GHC depends on Perl 5.6+ anyway, this patch introduces an
  equivalent effect to $* without using that special variable, by
  hooking into Perl's regex parsing process to add the /m flag.