Subject: bug#55294: Configure failure on Solaris 11.4

From: Eli Zaretskii <[email-masked]>
Date: Sat, 07 May 2022 08:40:15 +0300

> From: Steve Downey <[email-masked]>
> Date: Fri, 6 May 2022 15:58:39 -0400
> 
> On solaris 11.4, the system libc has a definition of sqrt leading configure to believe that linking libm is
> unnecessary.

Can you tell the details, please?  What is that definition of sqrt,
and what do you see in config.log when it is tested?

> Applying a patch locally to change
> AC_SEARCH_LIBS([sqrt], [m]) to 
> AC_SEARCH_LIBS([atan], [m])
> fixes the problem. 
> 
> atan was picked at random from the symbols that couldn't be found in building temacs. 

This is fragile, because we could have the same problem with atan, in
the future or on some other platform, if not here and now.  I think we
should understand better why using sqrt leads to the wrong conclusion,
and modify configure to avoid that.

Thanks.