anchor.diff:  
     gypFlagsUseSystemLibs = {
       use_system_bzip2 = true;
  -    use_system_ffmpeg = false; # FIXME: libavformat...
       use_system_flac = true;
       use_system_harfbuzz = false; # TODO
       use_system_icu = false; # FIXME: wrong version!
  
positive.code:   };
  
    defaultDependencies = [
      bzip2 ffmpeg flac # harfbuzz
      icu libevent expat libjpeg
      libpng libwebp libxml2 libxslt # skia
      speex sqlite # stlport
  
negative.code:     useOpenSSL = true;
      enableGnomeSupport = false;
      gnomeKeyringSupport = false;
      useProprietaryCodecs = true;
      enableCUPS = false;
    };
  
  