bug#42095: 28.0.50; Build fails on Windows/MinGW64

[Eli Zaretskii]

> Cc: peder@klingenberg.no, 42095@debbugs.gnu.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Sun, 28 Jun 2020 13:35:41 -0700
> 
> On 6/28/20 12:36 PM, Eli Zaretskii wrote:
> > do we have any tests in our test suite to test the getrandom
> > function?
> 
> No. Contributions would be welcome, I assume. Testing randomness is 
> nontrivial,
> though.

I just wanted something to cause the call to getrandom, just to see it
working and producing some reasonable value.  Would that be easy to
arrange?

Thanks.