ports/178419: Update to use USES=pkgconfig

[bdrewery at FreeBSD.org]

Synopsis: Update to use USES=pkgconfig

Responsible-Changed-From-To: freebsd-ports-bugs->bdrewery
Responsible-Changed-By: bdrewery
Responsible-Changed-When: Wed May 8 11:00:04 CDT 2013
Responsible-Changed-Why: 
I'll take it.

http://www.freebsd.org/cgi/query-pr.cgi?pr=178419