[Bug c++/92786] [c++11] static constexpr member link error

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92786

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Yes, this is
https://gcc.gnu.org/wiki/VerboseDiagnostics#missing_static_const_definition

In C++17 the static member is implicitly 'inline' which means the declaration
with an initializer is also a definition.