STATUS_CURRENT for threads under MSWin32

I'm having one last little problem with the thread exit
changes.

When a thread uses 'exit(status)', the threads.xs code gets
the exit code using STATUS_CURRENT.  Under Unix and Cygwin,
this works.  However, under MSWin32, STATUS_CURRENT is
always 0.

Is this a bug, or am I trying to use the wrong thing?

(If needed, email me directly for a copy of the module.)