ports/185938: graphics/truevision: Fix build with clang

[miwi at FreeBSD.org]

Synopsis: graphics/truevision: Fix build with clang

Responsible-Changed-From-To: freebsd-ports-bugs->miwi
Responsible-Changed-By: miwi
Responsible-Changed-When: Thu Jan 23 15:48:47 UTC 2014
Responsible-Changed-Why: 
I'll take it.

http://www.freebsd.org/cgi/query-pr.cgi?pr=185938