MFC r268994: C++ exception/unwind handling fix

  Add FreeBSD to the list of environments that needs to handle R_ARM_TARGET2
  relocations in unwind data as pc-relative indirect references.

Note that the commit log for r269792 incorrectly claims that it includes
this change, but I apparently fumbled it somehow, so this is the real MFC.
Document r269432, ttyu0 and ttyu1 default to 'onifconsole'
on ia64.

Sponsored by:	The FreeBSD Foundation
Document r269651, restore(8) fix when restoring UFS dump to
ZFS filesystem.

Sponsored by:	The FreeBSD Foundation
Document r269686, OpenSSL update to 1.0.1i.

Sponsored by:	The FreeBSD Foundation
Document r269774, new zfs(8) sysctls.

Sponsored by:	The FreeBSD Foundation
Document r269800, ping6(8) itimer reset when low interval and
small number of packets.

Sponsored by:	The FreeBSD Foundation
Document r269805, extra ifconfig(8) arguments are passable to
jail(8) ip4.addr and ip6.addr parameters.

Sponsored by:	The FreeBSD Foundation