Without this patch, Cabal is effectively "version-less" and all .cabal
files with a version requirement are unusable. Therefore I think that
this patch (or at least something equivalent) should be pushed to the
6.6.1 branch, too.

added --save-configure flag to clean. got some complaints that there was no way to avoid reconfiguring after a clean.  now if you use --save-configure, you should be able to.

As suggested by Claus Reinke in this ticket:
http://hackage.haskell.org/trac/hackage/ticket/105

sdist: make it work on Windows platforms by simplifying 'tar' invocation. Hopefully not at the cost of other plats (i.e., as-yet untested there..)"

When targetting Hugs, the Paths module now uses prefix-independent
paths relative to the location of the Main module of the program,
on all platforms.

For the Hugs target, this replaces the code using GetModuleFileNameA(),
which never worked.  Behaviour under GHC should be unchanged.