[Bug libstdc++/126949] [15/16/17 Regression] Can't construct an unordered set with a hasher whose ctor is explicit

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126949

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
libstdc++ patches need to be CC'd to the libstdc++ list:
https://gcc.gnu.org/lists.html