[Bug c++/92914] Hidden visibility incompatible with extern'd specialized explicit template instantiations

[steveire at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92914

--- Comment #1 from Stephen <steveire at gmail dot com> ---
www.open-std.org/jtc1/sc22AC/wg21/docs/papers/2017/p0537r0.html may be related
to this too.