[Bug c++/69387] undefined reference to constant in template

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69387

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Yes. This is a FAQ:
https://gcc.gnu.org/wiki/VerboseDiagnostics#missing_static_const_definition