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

[Jonathan Wakely]

On 22/10/16 19:39 +0300, Ville Voutilainen wrote:
>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. :)

OK for trunk and gcc-6-branch.