[Bug c++/81942] ICE on empty constexpr constructor with C++14

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81942

--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The patch LGTM, but I'll defer the final say to Jason/Nathan.