anchor.diff:    --enable-gpl \
     --enable-nonfree \
     --enable-small \
  -# audio: mp3 codec
     --enable-libmp3lame \
  -# video: h264 codec
  -#  --enable-libx264 \
  -# video: h265 codec
  -#  --enable-libx265 \
  -# video: vp9 codec
  -#  --enable-libvpx \
     --enable-libtheora \
  -# audio: ogg vorbis codec
     --enable-libvorbis \
  -# audio: opus codec
     --enable-libopus \
  -# audio: aac codec (high quality, nonfree)
     --enable-libfdk_aac \
  -#  video: subtitle renderer
  -#  --enable-libass \
  -# image: webp format support
  -#  --enable-libwebp \
  -# streaming: RTPM streaming protocol
  -#  --enable-librtmp \
  -# video: postprocessing
  -#  --enable-postproc \
  -
  -# audio: resampling
     --enable-avresample \
     --enable-libfreetype \
     --enable-openssl \
  
positive.code:     php7-phar \
      pkgconf \
      pkgconfig \
  #    rtmpdump \
  #    rtmpdump-dev \
      tar \
      wget \
  #    x264-dev \
  #    x265-dev \
      yasm \
      yasm-dev \
      zlib-dev \
  
negative.code:     freetype-dev \
      lame \
      lame-dev \
      libogg \
      libvpx \
      libogg-dev \
  