[Bug libstdc++/105375] std::packaged_task has no deduction guide.

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105375

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to raldone01 from comment #5)
> Thank you for your reply.
> What does that mean?

As it says at the link in comment 4, "The following behavior-changing defect
reports were applied retroactively to previously published C++ standards."

> Are defect reports updates for older standards?

Yes.

> Is it meant to be available at some point in c++17?

Yes.