[committed] libstdc++: Support VAX floats in std::strong_order

[Jonathan Wakely]

On Thu, 10 Mar 2022 at 11:53, Jonathan Wakely via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> Tested x86_64-linux, and basic soundness check on vax-dec-netbsdelf.

But apparently not enough of a soundness check, because
isnan(__builtin_nan("")) is true for VAX, so GCC seems to have a NaN
pattern, despite what I read online about the format.

Fix on the way ...