anchor.diff:  , youtubeSupport ? true, youtube-dl ? null
   , cacaSupport ? true, libcaca ? null
   , vaapiSupport ? false, libva ? null
  +, waylandSupport ? false, wayland ? null, libxkbcommon ? null
   }:
   
   assert x11Support -> (libX11 != null && libXext != null && mesa != null && libXxf86vm != null);
  
positive.code:     '';
    };
  }
  # TODO: Wayland support
  # TODO: investigate caca support
  # TODO: investigate lua5_sockets bug
  
negative.code:     "--enable-manpage-build"
      "--disable-build-date" # Purity
      "--enable-zsh-comp"
    ] ++ optional vaapiSupport "--enable-vaapi"
    ++ optional waylandSupport "--enable-wayland";
  
    configurePhase = ''
      python ${waf} configure --prefix=$out $configureFlags
  