[Bug libstdc++/79114] [6 Regression] std::throw_with_nested("string literal") is rejected

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79114

--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Ah yes, because throw_with_nested still depends on atomics in gcc-6-branch, and
so we need a dg-require- in the test (but only on the branch). I'll add that.