patch applied (ghc): Rejig the includes/ installation rules

[Ian Lynagh]

Sun Jan  9 10:11:58 PST 2011  Ian Lynagh <igloo at earth.li>
  * Rejig the includes/ installation rules
  They're a little nicer now, and a regression in the cygwin build is
  fixed (the $i in the destination wasn't surviving being passed through
  cygpath).

    M ./includes/ghc.mk -8 +12

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=ghc;a=darcs_commitdiff;h=20110109181158-3fd76-1d673afc7bff86bcc437ebbb39f6bb53ee9d538d.gz