detaching a thread from druntime <2.067

[Ellery Newcomer via Digitalmars-d-learn]

If I have a thread that I need to detach from druntime, I can call 
thread_detachInstance, but for 2.066, this function does not exist. Is 
there any way to do this in 2.066? I notice there is a 
thread_detachByAddr, but I'm not sure how to get a ThreadAddr out of a 
Thread..