Eli Zaretskii wrote:
> isn't there a way to test whether a platform supports IEEE
> FP representation except by looking for ieee754.h?  AFAICS, that
> header just defines a few data structures that any IEEE-compliant
> platform should be able to work with.

We can try using ieee754.h on non-GNU platforms and see what happens. In theory, 
there could be weird platforms where it doesn't work (as no standard specifies 
IEEE 754 layout); in practice, we'll probably be OK. So I created a Gnulib 
module for ieee754.h, merged it in, and installed the attached into master.