docs/170427: "PORTOPTIONS" should be "PORT_OPTIONS"

[A.J. Kehoe IV (Nanoman)]

>Number:         170427
>Category:       docs
>Synopsis:       "PORTOPTIONS" should be "PORT_OPTIONS"
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-doc
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Aug 06 21:30:01 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     A.J. Kehoe IV (Nanoman)
>Release:        9.0
>Organization:
Nanoman's Company
>Environment:
FreeBSD localhost 9.0-RELEASE-p3 FreeBSD 9.0-RELEASE-p3 #0: Tue Jun 12 02:52:29 UTC 2012     root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
In the FreeBSD Porter's Handbook, on the "Dependencies" page, "PORTOPTIONS" should be "PORT_OPTIONS".  "PORT_OPTIONS" is what's defined in the bsd.*.mk files, whereas "PORTOPTIONS" produces error messages.
>How-To-Repeat:

>Fix:
Replace every instance of "PORTOPTIONS" with "PORT_OPTIONS" in the FreeBSD Porter's Handbook.

I'd write a patch to submit, but the version of book.sgml that's available through CVS and CVSweb seems to be outdated.

>Release-Note:
>Audit-Trail:
>Unformatted: