anchor.diff:      nativeBuildInputs = with pkgs; [
         pkg-config
       ] ++ lib.optionals stdenv.isDarwin [
  -      xcbuild
         darwin.apple_sdk.frameworks.CoreText
       ];
       buildInputs = with pkgs; [
         pixman
         cairo
         pango
  +      giflib
       ];
     };
   
  
positive.code:   # ../../applications/video/epgstation
    epgstation = prev."epgstation-../../applications/video/epgstation".override (oldAttrs: {
      buildInputs = [ pkgs.postgresql ];
      nativeBuildInputs = [ final.node-pre-gyp final.node-gyp-build pkgs.which ] ++ lib.optionals stdenv.isDarwin [ pkgs.xcbuild ];
      meta = oldAttrs.meta // { platforms = lib.platforms.none; };
    });
  
    # NOTE: this is a stub package to fetch npm dependencies for
    # ../../applications/video/epgstation/client
    epgstation-client = prev."epgstation-client-../../applications/video/epgstation/client".override (oldAttrs: {
      nativeBuildInputs = lib.optionals stdenv.isDarwin [ pkgs.xcbuild ];
      meta = oldAttrs.meta // { platforms = lib.platforms.none; };
    });
  
  
negative.code:   });
  
    joplin = prev.joplin.override {
      nativeBuildInputs = [ pkgs.pkg-config ];
      buildInputs = with pkgs; [
        # required by sharp
        # https://sharp.pixelplumbing.com/install
  