patch applied (packages/Cabal): Add PackageIndex.dependencyGraph that builds a Graph

[Ian Lynagh]

Tue May  6 16:43:26 PDT 2008  Duncan Coutts <duncan at haskell.org>
  * Add PackageIndex.dependencyGraph that builds a Graph
  Useful for some more tricky queries.

    M ./Distribution/Simple/PackageIndex.hs +34

View patch online:
http://darcs.haskell.org/packages/Cabal/_darcs/patches/20080506234326-adfee-f3e9bb77388e5571e42bb3d9d22349b76f56410e.gz