anchor.diff:      + "--with-examples-dir=$out/share/doc/${name}/examples "
       + "--with-doc-dir=$out/share/doc/${name}";
   
  -  doCheck = true;
  -
     postInstall = ''
       ln -vs "$out/share/${name}/include" "$out/include"
  +    ln -vs "$out/share/${name}/lib" "$out/lib"
     '';
   
  +  doCheck = true;
  +  enableParallelBuilding = true;
  +
     meta = {
  -    homepage = http://www.gnu.org/software/gprolog/;
  -
  +    homepage = "http://www.gnu.org/software/gprolog/";
       description = "GNU Prolog, a free Prolog compiler with constraint solving over finite domains";
  +    license = "GPLv2+";
   
       longDescription = ''
         GNU Prolog is a free Prolog compiler with constraint solving
  
positive.code:       declarativity of logic programming.
      '';
  
      license = "GPLv2+";
  
      maintainers = [ stdenv.lib.maintainers.simons ];
      platforms = stdenv.lib.platforms.gnu;
    };
  
negative.code: { stdenv, fetchurl }:
  
  stdenv.mkDerivation rec {
    name = "gprolog-1.4.1";
  
    src = fetchurl {
      urls = [
        "mirror://gnu/gprolog/${name}.tar.gz"
        "http://www.gprolog.org/${name}.tar.gz"
      ];
      sha256 = "e2819ed9c426138d3191e4d97ae5121cf97e132eecf102400f87f1e372a05b72";
    };
  
    configurePhase = "cd src ;"
  