anchor.diff:  { stdenv, fetchurl, docutils, makeWrapper, perl, pkgconfig, python, which
   , ffmpeg, freefont_ttf, freetype, libass, libpthreadstubs, lua, lua5_sockets
  +, libuchardet, rubberband
   , x11Support ? true, libX11 ? null, libXext ? null, mesa ? null, libXxf86vm ? null
   , xineramaSupport ? true, libXinerama ? null
   , xvSupport ? true, libXv ? null
  
positive.code:   nativeBuildInputs = [ docutils makeWrapper perl pkgconfig python which ];
  
    buildInputs = [
      ffmpeg freetype libass libpthreadstubs lua lua5_sockets
    ] ++ optionals x11Support [ libX11 libXext mesa libXxf86vm ]
      ++ optional alsaSupport alsaLib
      ++ optional xvSupport libXv
  
negative.code: 
  stdenv.mkDerivation rec {
    name = "mpv-${version}";
    version = "0.17.0";
  
    src = fetchurl {
      url = "https://github.com/mpv-player/mpv/archive/v${version}.tar.gz";
      sha256 = "0vms3viwqcwl1mrgmf2yy4c69fvv7xpbkyrl693l6zpwynqd4b30";
    };
  
    patchPhase = ''
  