anchor.diff:    ++ flag gssSupport "negotiateauth"
     ++ lib.optional (!ffmpegSupport) "--disable-gstreamer"
     ++ flag webrtcSupport "webrtc"
  -  ++ flag geolocationSupport "mozril-geoloc"
     ++ lib.optional googleAPISupport "--with-google-api-keyfile=ga"
     ++ flag crashreporterSupport "crashreporter"
  -  ++ flag safeBrowsingSupport "safe-browsing"
     ++ lib.optional drmSupport "--enable-eme=widevine"
   
     ++ (if debugBuild then [ "--enable-debug" "--enable-profiling" ]
  
positive.code:     # possibilities on other platforms.
      # Lets save some space instead.
      "--with-system-nspr"
    ]
  
    ++ flag alsaSupport "alsa"
    ++ flag pulseaudioSupport "pulseaudio"
  
negative.code:   ]
  
    # and wants these
    ++ lib.optionals isTorBrowserLike ([
      "--with-tor-browser-version=${version}"
      "--enable-signmar"
      "--enable-verify-mar"
  