patch applied (packages/Cabal): Add PackageIndex.reverseDependencyClosure

[Ian Lynagh]

Tue May  6 16:49:02 PDT 2008  Duncan Coutts <duncan at haskell.org>
  * Add PackageIndex.reverseDependencyClosure
  It's similar to dependencyClosure but looks at reverse dependencies.
  For example it's useful to find all packages that depend on broken
  packages and are thus themselves broken.

    M ./Distribution/Simple/PackageIndex.hs -1 +22

View patch online:
http://darcs.haskell.org/packages/Cabal/_darcs/patches/20080506234902-adfee-09deee714d59d55e06e34f8b7d4abab08d61cc7e.gz