patch applied (cabal): Add support for manually en/disabled flags

[Ian Lynagh]

Wed Aug 27 10:01:05 PDT 2008  Ian Lynagh <igloo at earth.li>
  * Add support for manually en/disabled flags
  The immediate use for these is so that, in haddock, we can require
  ghc-paths normally, but in the GHC build we can manually turn off a flag
  so that this dependency isn't needed. We can't use a normal flag, or
  in the normal build Cabal would infer that the flag needs to be turned
  off if ghc-paths isn't available.

    M ./Distribution/PackageDescription.hs -2 +4
    M ./Distribution/PackageDescription/Configuration.hs -2 +6
    M ./Distribution/PackageDescription/Parse.hs -1 +3

View patch online:
http://darcs.haskell.org/cabal/_darcs/patches/20080827170105-3fd76-1c25affd29509e13ce196e164a9bf4d60cbea3c1.gz