[Bug libstdc++/61143] [4.9/4.10 Regression] Arithmetic exception on emplacing into unordered_map moved out

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=61143

--- Comment #6 from Marc Glisse <glisse at gcc dot gnu.org> ---
There was that whole discussion on how much sense it makes to make move
constructors noexcept when default constructors aren't...