anchor.diff:  
     xonotic = runCommandNoCC "xonotic${variant}-${version}" {
       inherit xonotic-unwrapped;
  -    buildInputs = [ makeWrapper ];
  +    nativeBuildInputs = [ makeWrapper copyDesktopItems ];
  +    desktopItems = [ desktopItem ];
       passthru = {
         inherit version;
         meta = meta // {
  
positive.code: { lib, stdenv, fetchurl, fetchzip, makeWrapper, runCommandNoCC, makeDesktopItem
  , xonotic-data
  , # required for both
    unzip, libjpeg, zlib, libvorbis, curl
  , # glx
  
negative.code:   '' + lib.optionalString (withSDL || withGLX) ''
      mkdir -p $out/share
      ln -s ${xonotic-unwrapped}/share/icons $out/share/icons
      copyDesktopItems
    '' + ''
      for binary in $out/bin/xonotic-*; do
        wrapProgram $binary --add-flags "-basedir ${xonotic-data}"
  