[Bug libstdc++/56166] std::string::clear() can throw despite being marked noexcept

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56166
--- Comment #12 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think __gnu_cxx::__rc_string has the same problem

There's a patch at https://gcc.gnu.org/ml/gcc-patches/2014-06/msg00278.html