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

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56166

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-01-31 22:24:21 UTC ---
I suppose ext/vstring is already fine. As regards the current
std::basic_string, if Jon has a quick fix, great, but I suggest not spending
much time on it.