ports/149678: Mk/bsd.port.mk: add a sanity check for OPTIONS

[edwin at FreeBSD.org]

Synopsis: Mk/bsd.port.mk: add a sanity check for OPTIONS

Responsible-Changed-From-To: freebsd-ports-bugs->portmgr
Responsible-Changed-By: edwin
Responsible-Changed-When: Sun Aug 15 15:40:09 UTC 2010
Responsible-Changed-Why: 
bsd.port.mk is portmgr territory (via the GNATS Auto Assign Tool)

http://www.freebsd.org/cgi/query-pr.cgi?pr=149678