Don't warn about deprecated 'POSIX' names

Change-Id: I70d02c432ff34a57278c593c73ff4bc0108096cd
Reviewed-on: http://review.couchbase.org/28010
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>