[ODE] Compiling Problem dHeightfield

[David Walters]

> Making a release is straightforward and should not be a limiting
> factor. Is everyone comfortable with the current state of the code? Is
> there anything that should be addressed first?

I would say that trimesh-heightfield collision would probably be good
as it's the only combination left (barring n/a cases like
heighfield/plane, heighfield/heightfield, etc.) I'll work on this just
now and - it should be ready in an hour or so assuming it goes as well
as I'm expecting.

Dave