ntp: import ntp-4.2.8p16

Security: NtpBUg3767, NtpBug3808, NtpBug3807 (CVE-2023-26555)
MFC after: immediately

MFV r294491: ntp 4.2.8p6.

Security: CVE-2015-7973, CVE-2015-7974, CVE-2015-7975
Security: CVE-2015-7976, CVE-2015-7977, CVE-2015-7978
Security: CVE-2015-7979, CVE-2015-8138, CVE-2015-8139
Security: CVE-2015-8140, CVE-2015-8158
With hat: so

MFV ntp-4.2.8p3 (r284990).

Approved by: roberto, delphij
Security: VuXML: 0d0f3050-1f69-11e5-9ba9-d050996490d0
Security: http://bugs.ntp.org/show_bug.cgi?id=2853
Security: https://www.kb.cert.org/vuls/id/668167
Security: http://support.ntp.org/bin/view/Main/SecurityNotice#June_2015_NTP_Security_Vulnerabi

MFV ntp 4.2.8p1 (r258945, r275970, r276091, r276092, r276093, r278284)

Thanks to roberto for providing pointers to wedge this into HEAD.

Approved by: roberto

Merge ntpd & friends 4.2.4p5 from vendor/ntp/dist into head. Next commit
will update usr.sbin/ntp to match this.

MFC after: 2 weeks

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

- Import the HEAD csup code which is the basis for the cvsmode work.