anchor.diff:  {stdenv, fetchurl, ghc, perl, gmp, ncurses}:
   
   stdenv.mkDerivation rec {
  -  version = "6.13.20100917";
  +  version = "7.0.1.20110217";
  +  label = "7.0.2-rc2";
     
     name = "ghc-${version}";
     
  
positive.code:   homepage = "http://haskell.org/ghc";
  
    src = fetchurl {
      url = "${homepage}/dist/current/dist/${name}-src.tar.bz2";
      sha256 = "0b5pg6688yfzd5zfaffjp21y933vp94h94ds85gwi156f4g3bkij";
    };
  
    buildInputs = [ghc perl gmp ncurses];
  
negative.code:     platforms = stdenv.lib.platforms.linux;
    };
  
  }
  