[Bug libstdc++/66338] std::forward_as_tuple() issue with single argument

[ville.voutilainen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66338

--- Comment #13 from Ville Voutilainen <ville.voutilainen at gmail dot com> ---
Right, that was fixed in the immediately following revision,
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=236823