anchor.diff:  
       homepage = http://www.informatik.uni-kiel.de/~pakcs/;
       license = stdenv.lib.licenses.bsd3;
  -    maintainers = [ stdenv.lib.maintainers.kkallio ];
  +    maintainers = [ stdenv.lib.maintainers.kkallio stdenv.lib.maintainers.simons ];
       platforms = stdenv.lib.platforms.linux;
     };
   }
  
positive.code: { stdenv, fetchurl, ghc, swiProlog, syb, mtl, makeWrapper, rlwrap, tk }:
  
  stdenv.mkDerivation rec {
    pname = "pakcs";
    version = "1.9.2";
    name = "${pname}-${version}";
  
    src = fetchurl {
      url = "http://www.informatik.uni-kiel.de/~pakcs/download/pakcs_src.tar.gz";
  
negative.code:     (cd $out/curry2prolog/ ; make)
  
      ensureDir $out/share/emacs/site-lisp/curry-pakcs
      for e in "$out/tools/emacs/"*.el ; do
        ln -s $out/tools/emacs/$e $out/share/emacs/site-lisp/curry-pakcs/;
      done
  
  