Use non-blocking connect() with ppoll() and timeout instead of alarm().

Use non-blocking connect() with ppoll() and timeout instead of alarm().
For hosts with multiple IP addrs this makes it possible to fall
over from an unresponsive IP to another.  This also replaces the
other connect(2) + connect_wait() calls with timed_connect() so the
-w option now works for more that just http.  OK sthen@ deraadt@