patch applied (cabal): Move expensive conviguration actions inside branch where they're used

[Duncan Coutts]

Mon Sep 17 01:58:34 PDT 2007  Duncan Coutts <duncan at haskell.org>
  * Move expensive conviguration actions inside branch where they're used
  We only need to configure the compiler and resolve any "Cabal-Version:"
  dependency when we're actually going to compile the Setup.hs program.
  We can otherwise save time by not calling ghc and ghc-pkg unnecessarily.
  (I only noticed this because I've got >150 registered packages which
  causes ghc and ghc-pkg to be very slow to start.)

    M ./Distribution/Simple/SetupWrapper.hs -6 +4