Official method for determining modular X module path?

[Andy Ritger]

With the new modular X server filesystem layout, how should 3rd party
vendors determine the path in which to install their X drivers?
My understanding is that the correct answer is for 3rd party
installation tools to run:

    pkg-config --variable=moduledir xorg-server

Is that correct?  If so, then I'd like to champion this with the
Linux distros.

The installer for the next NVIDIA Linux driver release will run
the above command; if that is successful and returns a directory
that exists, it will be used, otherwise the NVIDIA installer will
fall back to /usr/X11R6/lib/modules.

Is that the proper heuristic to use?

Thanks,
- Andy