cast time_t type variables to long where needed.

This makes res_calendar.c compile on OpenBSD and the same
cast is used in a lot of other places where time_t type vars are used.

(closes issue #15656)
Reported by: mvanbaak
Patches:
      2009081100-rescalendarcompilefix.diff.txt uploaded by mvanbaak (license 7)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@212343 65c4cc65-6c06-0410-ace0-fbb531ad65f3