darcs patch: Implement CLI flag --root-cmd for 'cabal install' as in #202 (+ 1 more)

Wed Mar 5 23:02:31 CET 2008 Andrea Vezzosi <sanzhiyan@gmail.com> * Implement CLI flag --root-cmd for 'cabal install' as in #202 It also adds the internal flag --only so we can avoid building a setup when build-type == Simple. This second patch (which is needed for the first) is for cabal: Wed Mar 5 22:44:43 CET 2008 Andrea Vezzosi <sanzhiyan@gmail.com> * Extend setupWrapper with setupWrapperEx so it can use an external program to gain privileges. This is needed to implement --root-cmd in cabal install.