anchor.diff:      cat $setupHook    >> $out/nix-support/setup-hook
     ";
   
  -  patch64 = ./x86_64-linux_patch;
  -
  -  # Thanks to Ian Lynagh ghc now works on x86_64-linux as well 
  -  patchPhase = if (stdenv.system == "x86_64-linux") then "patch -p2 < $patch64" else "";
  -
     configureFlags="--with-gmp-libraries=${gmp}/lib --with-readline-libraries=${readline}/lib";
   
     preConfigure = "
  -    # the presence of this file makes Cabal cry for happy while generating makefiles ...
  -    rm libraries/haskell-src/Language/Haskell/Parser.ly
       # still requires a hack for ncurses
       sed -i \"s|^\\\(ld-options.*$\\\)|\\\1 -L${ncurses}/lib|\" libraries/readline/readline.buildinfo.in
     ";
  
positive.code: {stdenv, fetchurl, readline, ghc, perl, m4, gmp, ncurses}:
  
  stdenv.mkDerivation (rec {
    name = "ghc-6.8.1";
    homepage = "http://www.haskell.org/ghc";
  
    src = map fetchurl [
      { url = "${homepage}/dist/stable/dist/${name}-src.tar.bz2";
        md5 = "8d47d4dcde96c31fe8bedcee7f99eaf1";
      }
      { url = "${homepage}/dist/stable/dist/${name}-src-extralibs.tar.bz2";
        md5 = "f91de87e7c0a3fe2f27c5a83212d9743";
      }
    ];
  
  
negative.code:   setupHook = ./setup-hook.sh;
  
    meta = {
      description = "The Glasgow Haskell Compiler";
    };
  
    postInstall = "
  