Log Message:
Update openntpd to 5.9p1, from Paul B. Henson in PR pkg/51092.

Changes since OpenNTPD 5.7p4
============================
* When a single "constraint" is specified, try all returned addresses
  until one succeeds, rather than the first returned address.
* Relaxed the constraint error margin to be proportional to the number
  of NTP peers, avoid constant reconnections when there is a bad NTP
  peer.
* Removed disabled hotplug sensor support.
* Added support for detecting crashes in constraint subprocesses.
* Moved the execution of constraints from the ntp process to the
  parent process, allowing for better privilege separation since the
  ntp process can be further restricted.
* Added pledge(2) support.
* Updated to require LibreSSL 2.3.2 or greater.
* Fixed high CPU usage when the network is down.
* Fixed various memory leaks.
* Switched to RMS for jitter calculations.
* Unified logging functions with other OpenBSD base programs.

OpenNTPD portable-specific changes:

* Added support for syncing time with the Realtime Clock (RTC) on OSes
  that require it.
* CFLAGS is no longer overridden by the build system.
* FreeBSD RTABLE support is disabled
* FreeBSD is no longer linked with -lmd to avoid hash function
  collisions, causing failures in constraint certificate loading.
* Fixed crashes due to __progname being used before initialized.
* Added Solaris 10 compatibility.
* Added --disable-https-constraint build option for explicitly
  disabling constraint support.
* Synced build system files with LibreSSL

Note that HTTPS TLS constraints are currently disabled in pkgsrc pending
evaluation of how best to deal with libressl.