ports/185509: net/mknbi: Support CC/CFLAGS properly

[miwi at FreeBSD.org]

Synopsis: net/mknbi: Support CC/CFLAGS properly

Responsible-Changed-From-To: freebsd-ports-bugs->miwi
Responsible-Changed-By: miwi
Responsible-Changed-When: Thu Jan 23 15:48:29 UTC 2014
Responsible-Changed-Why: 
I'll take it.

http://www.freebsd.org/cgi/query-pr.cgi?pr=185509