Cleanly make nvidia-driver gl.h override xorg-libraries gl.h

[José de Paula]

Hello. I've just bought a GeForce 6800 card, and it worked wonderfully
with the nvidia-driver port. I was wondering, is there a way to
cleanly make nVidia's gl.h (which is installed under
/usr/X11R6/share/doc/NVIDIA_GLX-1.0/gl.h) override xorg-libraries gl.h
(which is under /usr/X11R6/include/GL/gl.h)? Can I simply replace one
with the other? This means that I'd have to manually fiddle with this
everytime one of these ports is updated, which would be inconvenient
given that I update my ports very frequently.

So, what would you suggest?

FYI, I'm running 5.3-RELEASE, with CURRENT ports updated every few
hours. Thanks for any help.