*: fix SO_BINDTODEVICE. Kernel wants at least IFNAMSIZ bytes there.

networking/udhcp/socket.c

@@ -98,8 +98,8 @@ int FAST_FUNC udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf)
 		bb_perror_msg_and_die("SO_BROADCAST");
 
 	/* NB: bug 1032 says this doesn't work on ethernet aliases (ethN:M) */
-	if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, &inf, strlen(inf) + 1) == -1)
-		bb_perror_msg_and_die("SO_BINDTODEVICE");
+	if (setsockopt_bindtodevice(fd, inf))
+		xfunc_die(); /* warning is already printed */
 
 	memset(&addr, 0, sizeof(addr));
 	addr.sin_family = AF_INET;