[Bug libstdc++/95200] user-defined hash function is not copied correctly if unordered_map is declared using an incomplete type

[jevgenijsz1 at verifone dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95200

--- Comment #4 from jevgenijsz1 at verifone dot com ---
Jonathan,

Thank you for looking into this. I guess what confused me was copy assignment
requirements in 26.2.7 that explicitly say hash function is copied and the hash
function is available at the time of copy