Thread ctors/dtors

[dsimcha]

Would it be easy to put into core.thread a mechanism that would guarantee that
a set of callback functions were called from any newly created thread upon
creation, or by any thread just before termination?  Of course, by thread
termination, I mean if the thread terminates normally because it finishes its
job, not if it gets killed externally.

If this is reasonably implementable, do others feel it belongs in druntime?
If I wrote a good patch to do this, would it likely get accepted?  I think
ideas like this have been suggested before, but not really followed up on.