[v3 PATCH] Cross-port the latest resolution of LWG2756 and some bug-fixes to experimental::optional.

[Ville Voutilainen]

On 22 October 2016 at 19:34, Ville Voutilainen
<ville.voutilainen@gmail.com> wrote:
>     Cross-port the latest resolution of LWG2756 and some
>     bug-fixes to experimental::optional.
>     PR libstc++/77288
>     PR libstdc++/77727

And yes, I'll fix that first PR reference before committing the
ChangeLog changes. :)