Back out my backout, it was already posix compliant. Any new fields are

required to be "announced" by a new bit in sa_flags to indicate the
program is aware of and has taken care of them.  eg: SA_SIGINFO means
the program has used the sa_siginfo field (versus sa_handler).

lib/libc/net/res_send.c

@@ -665,7 +665,6 @@ res_send(buf, buflen, ans, anssiz)
 				pfd.fd = s;
 				pfd.events = POLLIN;
 				if (use_poll == 1) {
-					bzero(&sa, sizeof(sa));
 					sigemptyset(&sa.sa_mask);
 					sa.sa_flags = 0;
 					sa.sa_handler = SIG_IGN;