Add -stunServer arg for on-premises STUN

common/rfb/ServerCore.cxx

@@ -221,6 +221,10 @@ rfb::StringParameter rfb::Server::publicIP
 ("publicIP",
  "The server's public IP, for UDP negotiation. If not set, will be queried via the internet.",
  "");
+rfb::StringParameter rfb::Server::stunServer
+("stunServer",
+ "Use this STUN server for querying the server's public IP. If not set, a hardcoded list is used.",
+ "");
 
 rfb::IntParameter rfb::Server::udpFullFrameFrequency
 ("udpFullFrameFrequency",
@@ -236,4 +240,4 @@ static void bandwidthPreset() {
 rfb::PresetParameter rfb::Server::preferBandwidth
 ("PreferBandwidth",
  "Set various options for lower bandwidth use. The default is off, aka to prefer quality.",
- false, bandwidthPreset);
+ false, bandwidthPreset);