patch applied (packages/Cabal): First attempt at a cabal-setup command

[Simon Marlow]

Fri Mar  3 08:22:33 PST 2006  Simon Marlow <simonmar at microsoft.com>
  * First attempt at a cabal-setup command
  cabal-setup is a replacement for 'runhaskell Setup.hs'.  It accepts
  exactly the same commands.  Additionally, the following new features
  are provided:
  
   * Setup.{hs,lhs} is optional.  If omitted, cabal-setup behaves just
     like Distribution.Simple.defaultMain.
  
   * If the .cabal file contains a cabal-version field, then Setup.hs
     is built using an appropriate version of Cabal.  This might entail
     creating Setup.hs if it doesn't exist.
  
   * cabal-setup interprets the options --with-compiler and --with-hc-pkg
     to determine the compiler used to compile Setup.hs.
  
  Later, we could add support for building multiple packages in
  dependency order, as per recent discussions on libraries at haskell.org.

    A ./cabal-setup/
    A ./cabal-setup/CabalSetup.hs
    A ./cabal-setup/Setup.hs
    A ./cabal-setup/cabal-setup.cabal