[Bug c++/77923] GCC emits "declares nothing" diagnostic on meaningful declarations.

[eric at efcs dot ca]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77923

--- Comment #1 from Eric Fiselier <eric at efcs dot ca> ---
Ping. I keep hitting this more and more.

GCC seems to be warning because the declaration includes the CXX scope
specifier "::foo". Removing the "::" seems to work. However, removing the "::"
causes the code to take on a different semantic meaning.

The warning shouldn't be issued in either case.