[PATCH RFC] allow inline intrinsics for __ieee754_sqrt/f

[jon@beniston.com]

Hi Wilco,

>The best option is to let the compiler inline sqrt - it knows when it is
feasible and avoids 
>having to add lots of target specific inline assembly code which is hard to
maintain.
>
>In GLIBC I renamed all __ieee754_sqrt(f) uses to sqrt(f) and added
-fno-math-errno 
>which allows compilers to inline sqrt on all targets. libm/common already
uses 
>-fno-math-errno, but could be used in all of libm safely.

That works for most of the uses of __ieee754_sqrt, except, I think, for
those in w_sqrt.c / wf_sqrt.c, that implement sqrt & sqrtf.  If the target
didn't have a builtin for sqrt, you'd end up with a recursive call, no?

Cheers,
Jon