anchor.diff:  {stdenv, fetchurl, zlib, openssl, libre, librem, pkgconfig
   , cairo, mpg123, gstreamer, gst_ffmpeg, gst_plugins_base, gst_plugins_bad
   , gst_plugins_good, alsaLib, SDL, libv4l, celt, libsndfile, srtp, ffmpeg
  -, gsm, speex, portaudio, spandsp, libuuid
  +, gsm, speex, portaudio, spandsp, libuuid, ccache
   }:
   stdenv.mkDerivation rec {
     version = "0.4.20";
  
positive.code:     "LIBREM_PATH=${librem}"
      ''PREFIX=$(out)''
      "USE_VIDEO=1"
  
      "USE_ALSA=1" "USE_AMR=1" "USE_CAIRO=1" "USE_CELT=1" 
      "USE_CONS=1" "USE_EVDEV=1" "USE_FFMPEG=1"  "USE_GSM=1" "USE_GST=1" 
  
negative.code:   buildInputs = [zlib openssl libre librem pkgconfig
      cairo mpg123 gstreamer gst_ffmpeg gst_plugins_base gst_plugins_bad gst_plugins_good
      alsaLib SDL libv4l celt libsndfile srtp ffmpeg gsm speex portaudio spandsp libuuid
      ccache
      ];
    makeFlags = [
      "LIBRE_MK=${libre}/share/re/re.mk"
  