patch applied (cabal): add data-dir field to package config

[Duncan Coutts]

Fri May  9 06:04:48 PDT 2008  Bertram Felgenhauer <int-e at gmx.de>
  * add data-dir field to package config
  Cabal will look for data files to install relative to the directory given
  in the data-dir field, allowing package authors to better structure their
  source tree. There's no behavioural change by default.

    M ./Distribution/PackageDescription.hs +2
    M ./Distribution/PackageDescription/Parse.hs +3
    M ./Distribution/Simple/Install.hs -1 +1
    M ./Distribution/Simple/SrcDist.hs -2 +3

View patch online:
http://darcs.haskell.org/cabal/_darcs/patches/20080509130448-ef904-058af697896fcffaf3d8e798e8ac785b7b13d1cf.gz