bug#36609: 27.0.50; Possible race-condition in threading implementation

[Eli Zaretskii]

> Date: Fri, 12 Jul 2019 10:47:37 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 36609@debbugs.gnu.org
> 
> Please describe what this program tries to accomplish, and how.  It's
> not easy to reverse-engineer that from 200 lines of non-trivial code.
> It's possible that the reason(s) for the freeze will be apparent from
> describing your implementation ideas.

Oh, and one more question: does the value of the global variable
last_thread_error tell something interesting at that point?