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