NIS lookups fails for getpwuid in presense of repeated signal event

Issue

• A program doing a kind of profiling of itself using alarm()/SIGALRM each second, gets stuck in getpwuid() and similar calls trying to get UID which is in NIS.
• Whenever there is an UDP packet loss, ALRM signal arrives while the getpwuid() call is waiting in poll() for a  reply from NIS and getpwuid never returns.