[PATCH roland/test-unsupported] Let tests result in UNSUPPORTED; use that for unbuildable C++ cases

[Roland McGrath]

> RFE: Could we have a target that actually lists information about the tests
> *before* you run them? That way a developer can verify what is about to
> get tested?

I don't know exactly what you have in mind.  It seems orthogonal to what
I've worked on here.  Feel free to post such a change.


Thanks,
Roland