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

[Eli Zaretskii]

> From: dick.r.chiang@gmail.com
> Cc: 36609@debbugs.gnu.org
> Date: Thu, 10 Jun 2021 17:36:13 -0400
> 
> EZ> Is it, really?
> 
> Yes.  While I can't claim to be any more knowledgeable, the naivete of someone
> protesting thread atomicity based on word-size is stunningly apparent.

I'm okay with replacing the simple increments and decrements of that
variable with atomic ones, using the likes of __atomic_fetch_add
intrinsics of GCC, if that solves the problem.  Did you try that?