anchor.diff:      ++ optional xineramaSupport    libXinerama
       ++ optional xvSupport          libXv
       ++ optional youtubeSupport     youtube-dl
  +    ++ optional zimgSupport        zimg
       ++ optional stdenv.isDarwin    libiconv
       ++ optional stdenv.isLinux     nv-codec-headers
       ++ optionals cddaSupport       [ libcdio libcdio-paranoia ]
  +    ++ optionals drmSupport        [ libdrm mesa ]
       ++ optionals dvdnavSupport     [ libdvdnav libdvdnav.libdvdread ]
       ++ optionals waylandSupport    [ wayland wayland-protocols libxkbcommon ]
       ++ optionals x11Support        [ libX11 libXext libGLU_combined libXxf86vm libXrandr ]
  -    ++ optionals vulkanSupport     [ shaderc vulkan-headers vulkan-loader ]
  +    ++ optionals vulkanSupport     [ libplacebo shaderc vulkan-headers vulkan-loader ]
       ++ optionals stdenv.isDarwin (with darwin.apple_sdk.frameworks; [
         CoreFoundation Cocoa CoreAudio
       ]);
  
positive.code: assert bluraySupport      -> available libbluray;
  assert bs2bSupport        -> available libbs2b;
  assert cacaSupport        -> available libcaca;
  assert cddaSupport        -> all available [libcdio libcdio-paranoia];
  assert cmsSupport         -> available lcms2;
  assert drmSupport         -> available libdrm;
  assert dvdnavSupport      -> available libdvdnav;
  assert dvdreadSupport     -> available libdvdread;
  assert jackaudioSupport   -> available libjack2;
  assert libpngSupport      -> available libpng;
  assert openalSupport      -> available openalSoft;
  assert pulseSupport       -> available libpulseaudio;
  assert rubberbandSupport  -> available rubberband;
  assert screenSaverSupport -> available libXScrnSaver;
  assert sdl2Support        -> available SDL2;
  assert speexSupport       -> available speex;
  assert theoraSupport      -> available libtheora;
  assert vaapiSupport       -> available libva;
  assert vapoursynthSupport -> available vapoursynth;
  assert vdpauSupport       -> available libvdpau;
  assert waylandSupport     -> all available [ wayland wayland-protocols libxkbcommon ];
  assert x11Support         -> all available [ libGLU_combined libX11 libXext libXxf86vm libXrandr ];
  assert xineramaSupport    -> x11Support && available libXinerama;
  assert xvSupport          -> x11Support && available libXv;
  assert youtubeSupport     -> available youtube-dl;
  
  let
    # Purity: Waf is normally downloaded by bootstrap.py, but
  
negative.code:   configureFlags = [
      "--enable-libmpv-shared"
      "--enable-manpage-build"
      "--disable-libmpv-static"
      "--disable-static-build"
      "--disable-build-date" # Purity
  