anchor.diff: -{ stdenv
  +{ lib
  +, mkDerivation
   , fetchFromGitHub
   , cmake
  -, wrapQtAppsHook
   , dxflib
   , eigen
   , flann
  
positive.code:   nativeBuildInputs = [
      cmake
      eigen # header-only
      wrapQtAppsHook
    ];
  
    buildInputs = [
  
negative.code:     "-DPLUGIN_IO_QRDB=OFF" # Riegl rdblib is proprietary; not packaged in nixpkgs
    ];
  
    meta = with lib; {
      description = "3D point cloud and mesh processing software";
      homepage = "https://cloudcompare.org";
      license = licenses.gpl2Plus;
  