> -mspeculative-load-hardening Clang now has an option to enable Speculative Load Hardening. I wonder -- which targets support this flag? And which ones need

> -mspeculative-load-hardening Clang now has an option to enable Speculative Load Hardening. I wonder -- which targets support this flag? And which ones need it (i.e. which are susceptible)? Also, I didn't see it in the changelog -- does libc++ have std::execution::* yet?