anchor.diff:      ${if x11Support then "--enable-x11" else ""}
       --disable-xanim
       --disable-ivtv
  +    --enable-vidix
  +    --enable-fbdev
     '';
   
     NIX_LDFLAGS = if x11Support then "-lX11 -lXext" else "";
  
positive.code:     '';
  
    crossAttrs = {
      preConfigure = ''
        configureFlags="`echo $configureFlags |
          sed -e 's/--build[^ ]\+//' \
          -e 's/--host[^ ]\+//' \
          -e 's/--codecsdir[^ ]\+//' \
          -e 's/--enable-runtime-cpudetection//' `"
        configureFlags="$configureFlags --target=${stdenv.cross.arch}-linux
          --cc=$crossConfig-gcc --as=$crossConfig-as"
      '';
    };
  
  
negative.code: 
    buildNativeInputs = [ yasm ];
  
    preConfigure = ''
      tar xf ${ffmpeg.src}
      mv ffmpeg* ffmpeg
    '';
  
    configureFlags = ''
      ${if cacaSupport then "--enable-caca" else "--disable-caca"}
      ${if dvdnavSupport then "--enable-dvdnav --enable-dvdread --disable-dvdread-internal" else ""}
  