X11 ports

So I've never dealt with porting X11 programs before. Since we all use a non-MacPorts X11 now, does that make it acceptable to write outside ${prefix] for X11 ports? Specifically, this submission writes to /usr/X11R6/bin/ and /usr/X11R6/lib (via destroot). Please advise. http://trac.macosforge.org/projects/macports/ticket/7488 Mark