[Bug c++/80789] Better error for passing lambda with capture as function pointer

[egallager at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80789

--- Comment #2 from Eric Gallager <egallager at gcc dot gnu.org> ---
not sure whether to cc the C++ FE maintainers or the diagnostics maintainers on
this...