bug#32605: [w64] (random) never returns negative

[Eli Zaretskii]

> From: Andy Moreton <andrewjmoreton@gmail.com>
> Date: Sat, 14 Aug 2021 09:31:06 +0100
> 
> I'm not an expert on random numbers either, and your efforts are not an
> annoyance, but I am puzzled why you so strongly prize performance over
> correctness in this instance.

Because I have no idea how important the "correctness" part is, or
why.  OTOH, this stuff, when used, tends to be in the inner loops, so
performance matters.