The exploit that you mentioned,
only talks about escaping from chroot, not elevating privelige,
I am not a programmer, and probably couldn't pull this off,
so I wouldn't be afraid of letting my friend compile something
as a normal user. Setting up the chroot jail with a compiler
isn't a trivial task either. Since I am not an admin at a nuclear
weapons lab, I don't have to worry about it. If you don't trust the guy,
there's no easy way to give him access without taking some small
risk.