anchor.diff:  , which
   
   , alsa-lib
  -, enca
   , ffmpeg
   , freefont_ttf
   , freetype
  
positive.code:     "--${boolEn (libdvdnav != null)}-dvdnav"
      # FIXME
      #"--${boolEn (libcdio != null)}-cdda"
      "--${boolEn (enca != null)}-enca"
      #"--${boolEn ( != null)}-uchardet"
      "--${boolEn (rubberband != null)}-rubberband"
      "--${boolEn (lcms2 != null)}-lcms2"
  
negative.code: 
    buildInputs = [
      alsa-lib
      ffmpeg
      freefont_ttf
      freetype
  