anchor.diff:          url = "http://haskell.org/ghc/dist/${version}/ghc-${version}-x86_64-unknown-linux.tar.bz2";
           sha256 = "14jvvn333i36wm7mmvi47jr93f5hxrw1h2dpjvqql0rp00svhzzg";
         }
  -    else if (stdenv.system == "i686-darwin" || stdenv.system == "x86_64-darwin") then
  +    else if stdenv.system == "i686-darwin" then
         fetchurl {
           # Idem.
           url = "http://haskell.org/ghc/dist/${version}/maeder/ghc-${version}-i386-apple-darwin.tar.bz2";
  
positive.code:         [ $(./main) == "yes" ]
        '';
  
    meta = {
      homepage = "http://haskell.org/ghc";
      description = "The Glasgow Haskell Compiler";
      maintainers = [ stdenv.lib.maintainers.simons ];
      platforms = stdenv.lib.platforms.linux ++ stdenv.lib.platforms.darwin;
    };
  }
  
negative.code: {stdenv, fetchurl, perl, libedit, ncurses, gmp}:
  
  assert stdenv.system == "i686-darwin" || stdenv.system == "x86_64-linux" || stdenv.system == "i686-linux";
  
  stdenv.mkDerivation rec {
    version = "6.10.1";
  