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