[Bug c++/68093] [concepts] friend function declarations that differ only by constraints are rejected as redefinitions

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68093

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
*** Bug 86978 has been marked as a duplicate of this bug. ***