LibcExit called std::exit, which ran the static destructors of the libraries
before the guest exit handlers. A guest handler that freed memory then locked
a destroyed std::mutex, which throws, and a noexcept guest destructor ended in
std::terminate. The guest handlers now run first, while the library objects
are alive.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>