anchor.diff:  assert libpngSupport -> libpng != null;
   assert youtubeSupport -> youtube-dl != null;
   assert cacaSupport -> libcaca != null;
  +assert waylandSupport -> (wayland != null && libxkbcommon != null);
   
   let
     inherit (stdenv.lib) optional optionals optionalString;
  
positive.code:     "--enable-manpage-build"
      "--disable-build-date" # Purity
      "--enable-zsh-comp"
    ] ++ optional vaapiSupport "--enable-vaapi";
  
    configurePhase = ''
      python ${waf} configure --prefix=$out $configureFlags
  
negative.code:     ++ optional youtubeSupport youtube-dl
      ++ optional sdl2Support SDL2
      ++ optional cacaSupport libcaca
      ++ optional vaapiSupport libva
      ++ optionals waylandSupport [ wayland libxkbcommon ];
  
    enableParallelBuilding = true;
  
  