anchor.diff:  
     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 ""}
  
positive.code: { alsaSupport ? true, xvSupport ? true, theoraSupport ? true, cacaSupport ? true
  , xineramaSupport ? true, randrSupport ? true, dvdnavSupport ? true
  , stdenv, fetchurl, x11, freetype, fontconfig, zlib
  , alsaLib ? null, libXv ? null, libtheora ? null, libcaca ? null
  , libXinerama ? null, libXrandr ? null, libdvdnav ? null
  , cdparanoia ? null, cddaSupport ? true
  
negative.code:     '';
  
    crossAttrs = {
      dontSetConfigureCross = true;
      # Some things (vidix) are nanonote specific. Once someone cares, we can make options from them.
      preConfigure = preConfigure + ''
        configureFlags="`echo $configureFlags |
          sed -e 's/--codecsdir[^ ]\+//' \
          -e 's/--enable-runtime-cpudetection//' `"
        configureFlags="$configureFlags --target=${stdenv.cross.arch}-linux
          --enable-cross-compile --cc=$crossConfig-gcc --as=$crossConfig-as
          --disable-vidix-pcidb --with-vidix-drivers=no --host-cc=gcc"
      '';
    };
  
  