Use poll() instead of select() in res_timing_pthread to avoid stack corruption.

This code did not properly check FD_SETSIZE to ensure that it did not try to
select() on fds that were too large.  Switching to poll() removes the limitation
on the maximum fd value.

(closes issue #15915)
Reported by: keiron

(closes issue #17187)
Reported by: Eddie Edwards

(closes issue #16494)
Reported by: Hubguru

(closes issue #15731)
Reported by: flop

(closes issue #12917)
Reported by: falves11

(closes issue #14920)
Reported by: vrban

(closes issue #17199)
Reported by: aleksey2000

(closes issue #15406)
Reported by: kowalma

(closes issue #17438)
Reported by: dcabot

(closes issue #17325)
Reported by: glwgoes

(closes issue #17118)
Reported by: erikje

possibly other issues, too ...


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@278465 65c4cc65-6c06-0410-ace0-fbb531ad65f3