MFC r251424:

New install flags were merged to 9-STABLE and will appear in
FreeBSD-9.2.

Sponsored by:	DARPA, AFRL
Submitted by:	ru


git-svn-id: svn://svn.freebsd.org/base/stable/9@251611 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Merge remote-tracking branch 'upstream/svn_stable_9' into svn_stable_9