Ensure that all areas that previously used select(2) now use poll(2), with implementa...

Ensure that all areas that previously used select(2) now use poll(2), with implementations that need poll(2) implemented with select(2) safe against 1024-bit overflows.

This is a followup to the fix for the pthread timer in 1.6.2 and beyond, fixing
a potential crash bug in all supported releases.

(closes issue #17678)
 Reported by: russell
Branch: https://origsvn.digium.com/svn/asterisk/team/tilghman/ast_select

Review: https://reviewboard.asterisk.org/r/824/

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@284478 65c4cc65-6c06-0410-ace0-fbb531ad65f3