patch applied (cabal): Print a more helpful message when haddock's ghc version doesn't match

[Duncan Coutts]

Wed Apr 22 02:32:40 PDT 2009  Duncan Coutts <duncan at haskell.org>
  * Print a more helpful message when haddock's ghc version doesn't match
  Eg now says something like:
  cabal: Haddock's internal GHC version must match the configured GHC version.
  The GHC version is 6.8.2 but haddock is using GHC version 6.10.1

    M ./Distribution/Simple/Haddock.hs -5 +11

View patch online:
http://darcs.haskell.org/cabal/_darcs/patches/20090422093240-adfee-17ced84623fbb3685a36d1d28d9b29b7850fd62d.gz