anchor.diff:      (enFlag "vorbis-encoder" (libvorbis != null) null)
       (enFlag "wave-encoder" true null)
       # FIXME: wavpack support
  -    #(enFlag "wavpack" (wavpack != null) null)
  +    (enFlag "wavpack" (wavpack != null) null)
       (wtFlag "zeroconf" (avahi != null && dbus != null) "avahi")
       (enFlag "zlib" (zlib != null) null)
       (enFlag "zzip" (zziplib != null) null)
  
positive.code: , sqlite
  , systemd_lib
  #, twolame
  #, wavpack
  , yajl
  , zlib
  , zziplib
  
negative.code:     soxr
      sqlite
      systemd_lib
      wavpack
      yajl
      zlib
      zziplib
  