void receive_udp(string host, string msg, int hostport)
Handle a received UDP message.
This function is called for every message received on the UDP
port. Usually it is passed on to some object that handles
inter mud communications.
The driver first calls receive_udp(). If that method doesn't exist
and if the driver is compiled with USE_DEPRECATED, it will then
The 'hostport' argument was added in 3.2.1.
LDMud 3.2.9 renamed this method from receive_imp(); that old version
is supported if the driver is compiled with USE_DEPRECATED.
send_udp(E), query_udp_port(E), send_imp(E), query_imp_port(E)