patch applied (ghc-6.8/ghc): Make DESTDIR work again

[Ian Lynagh]

Sun Sep 16 01:43:39 PDT 2007  sven.panne at aedion.de
  * Make DESTDIR work again
  installPackage is a horror, using --force is probably not the perfect way
  to make DESTDIR functionality work again, but given the current state of
  affairs, I can't find a quick and clean solution.
  
  MERGE TO STABLE

    M ./libraries/installPackage.hs -1 +1