X11 and tilcdc driver

I’m building X11 for the BBB using Rob Clark’s tilcdc driver, which is part of Robert Wilson’s
standard kernel. However, I’m stuck on configuring the Mesa library; at a guess it will need
llvm for software rendering, but there seems no way of connecting Mesa to the actual video
driver, along lines of eg: xf86-video-fbdev. It must be possible, since there are a number of
GUIs around, but does anyone know how?

Thanks - Will

Interested to know this too