anchor.diff:  , oceSupport ? true, opencascade
   , ngspiceSupport ? true, libngspice
   , swig, python, pythonPackages
  -, lndir, withLibraries ? true, with3DPackages ? false
  +, lndir, with3DPackages ? false
   }:
   
   assert ngspiceSupport -> libngspice != null;
   
   with lib;
   let
  -  mkLib = version: name: sha256: stdenv.mkDerivation {
  +  mkLib = version: name: sha256: attrs: stdenv.mkDerivation ({
       name = "kicad-${name}-${version}";
       src = fetchFromGitHub {
         owner = "KiCad";
  
positive.code:   meta = {
      description = "Free Software EDA Suite";
      homepage = http://www.kicad-pcb.org/;
      license = [ licenses.gpl2 ] ++ optional (withLibraries || with3DPackages) licenses.cc-by-sa-40;
      maintainers = with maintainers; [ berce ];
      platforms = with platforms; linux;
    };
  
negative.code:     nativeBuildInputs = [
        cmake
      ];
    } // attrs);
  
  in stdenv.mkDerivation rec {
    name = "kicad-${version}";
  