- check_ntp:

- check_ntp:
  - now roughly feature-complete.
  - various bugfixes, esp. offset calculation.
  - enhanced the asynchronous offset polling to set requests that
    haven't recieved a response in >= 1 second to stale and retransmit them,
    which results in much better performance on unreliable networks.
  - we only spend timeout/2 seconds polling offsets, and if we don't get
    everything by that point we work with what we have and set status to
    warning/critical depending on how much data we have.
  - set the same defaults as the perl script.
- commit changes to configure.in to support automatic building of check_apt
  (if apt-get is installed and regex libraries available) and check_ntp
  (unconditionally), now defaulting to check_ntp.c instead of the perl script.
  if this is an issue we can back out the commit of course.  an eye
  should be kept on check_ntp building and running correctly in different
  environments, esp. 64-bit and big-endian platforms, and those with more
  "esoteric" API's (do any of the platforms not have poll()?).
- similar changes to Makefile.am's.
- common.h: add statement to include sys/poll.h
- runcmd.c: exit STATE_UNKNOWN if execve() fails.

git-svn-id: https://nagiosplug.svn.sourceforge.net/svnroot/nagiosplug/nagiosplug/trunk@1386 f882894a-f735-0410-b71e-b25c423dba1c