[Bug cobol/119244] cobol/libgcobol should allow libquadmath to provide 128b floating support.

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119244

--- Comment #20 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #18)
> I think s390x-linux is similar to aarch64-linux here, neither has
> libquadmath support.

However, libquadmath works fine on aarch64-darwin, so it is a possible
--as-needed solution for the C23 interfaces (that is what I'm doing at the
moment)

> Just long double is always IEEE quad on aarch64-linux and on s390x-linux it
> is configurable, one can choose between IEEE double and IEEE quad and for
> the latter needs some glibc support (though years older than the *f128 APIs).

I'll extend my logic to match what you put in comment #16, it would be good to
cover the case where long double == 128b ieee754.