ports/152753: audio/mumble: fix build with upcoming Qt-4.7

[edwin at FreeBSD.org]

Synopsis: audio/mumble: fix build with upcoming Qt-4.7

Responsible-Changed-From-To: freebsd-ports-bugs->makc
Responsible-Changed-By: edwin
Responsible-Changed-When: Wed Dec 1 21:10:12 UTC 2010
Responsible-Changed-Why: 
Submitter has GNATS access (via the GNATS Auto Assign Tool)

http://www.freebsd.org/cgi/query-pr.cgi?pr=152753