anchor.diff:      #--with-external-dvdnav  Use external dvdnav library (not recommended)
       "--with-imagemagick"
       "--with-libflac"
  -    "--with-speex"
  +    #"--with-speex"
       "--with-theora"
       "--with-vorbis"
       "--with-wavpack"
  
positive.code: 
    buildInputs = [
      aalib
      alsaLib
      ffmpeg
      flac
      fontconfig
  
negative.code: , perl
  
  , aalib
  , alsa-lib
  , ffmpeg
  , flac
  , fontconfig
  