Fix possible login(1) argument injection in telnetd(8). [SA-16:36]

Fix possible login(1) argument injection in telnetd(8). [SA-16:36]
Fix link_ntoa(3) buffer overflow in libc. [SA-16:37]
Fix possible escape from bhyve(8) virtual machine. [SA-16:38]
Fix warnings about valid time zone abbreviations. [EN-16:19]
Update timezone database information. [EN-16:20]

Security:	FreeBSD-SA-16:36.telnetd
Security:	FreeBSD-SA-16:37.libc
Security:	FreeBSD-SA-16:38.bhyve
Errata Notice:	FreeBSD-EN-16:19.tzcode
Errata Notice:	FreeBSD-EN-16:20.tzdata
Approved by:	so

git-svn-id: svn://svn.freebsd.org/base/releng/10.3@309634 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f