1.5.20110418 does not build but it looks like it may be partially a miniupnp install issue. It fails to install portlistingparse.h and miniupnpctypes.h.
upnpDiscover():53 is in miniupnpc.h as
const char * minissdpdsock, int sameport,
int ipv6,
int * error);
net.cpp calls it as:
There may be more, that was the first one I hit though.