anchor.diff:  
     meta = with lib; {
       description = "High performance layout viewer and editor with support for GDS and OASIS";
  -    license = with licenses; [ gpl3 ];
  +    license = with licenses; [ gpl2Plus ];
       homepage = "https://www.klayout.de/";
  +    changelog = "https://www.klayout.de/development.html#${version}";
       platforms = platforms.linux;
       maintainers = with maintainers; [ knedlsepp ];
     };
  
positive.code: { lib, mkDerivation, fetchFromGitHub, fetchpatch
  , python3, ruby, qtbase, qtmultimedia, qttools, qtxmlpatterns
  , which, perl, makeWrapper
  }:
  
  mkDerivation rec {
    pname = "klayout";
    version = "0.27.3";
  
    src = fetchFromGitHub {
      owner = "KLayout";
      repo = "klayout";
      rev = "v${version}";
      sha256 = "sha256-6g/QoR16rhUfxhH4JxL6EERcoPVG/6MOxUlo6K/WoE0=";
    };
  
    postPatch = ''
  
negative.code:   buildPhase = ''
      runHook preBuild
      mkdir -p $out/lib
      ./build.sh -qt5 -prefix $out/lib -option -j$NIX_BUILD_CORES
      runHook postBuild
    '';
  
  