anchor.diff:  in
   stdenv.mkDerivation rec {
     name = "slic3r-prusa-edition-${version}";
  -  version = "1.39.2";
  +  version = "1.40.0";
   
     enableParallelBuilding = true;
   
     buildInputs = [
       cmake
  +    curl
       perl
       makeWrapper
       eigen
  
positive.code: 
      # it seems we need to copy the icons...
      mkdir -p $out/bin/var
      cp ../resources/icons/* $out/bin/var/
      cp -r ../resources $out/bin/
    '';
  
    src = fetchFromGitHub {
      owner = "prusa3d";
      repo = "Slic3r";
      sha256 = "0vbqkmd2yqi469ijqm4wyzjmq9w1kwiy8av1kchm4429z5hpmxcd";
      rev = "version_${version}";
    };
  
  
negative.code: { stdenv, fetchFromGitHub, makeWrapper, which, cmake, perl, perlPackages,
    boost, tbb, wxGTK30, pkgconfig, gtk3, fetchurl, gtk2, bash, libGLU,
    glew, eigen, curl }:
  let
    AlienWxWidgets = perlPackages.buildPerlPackage rec {
      name = "Alien-wxWidgets-0.69";
  