bug#55294: Configure failure on Solaris 11.4

[Eli Zaretskii]

> From: Steve Downey <sdowney@gmail.com>
> Date: Tue, 10 May 2022 00:46:15 -0400
> Cc: eggert@cs.ucla.edu, 55294@debbugs.gnu.org
> 
>  If so, perhaps to make this test more future-proof, we should try
>  several functions, not just one?
> 
> And gate linking libm on any of them being unavailable. But writing that 
> would mean having to resuscitate my
> M4 knowledge. 

I think it's easy enough, and I'm sure Paul will be able to do that.
In the improbable case that he doesn't, I will.

Thanks.