https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97182
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- The consequence of not using SYS_futex is that we use a mutex + condition variable for some synchronization, which is obviously suboptimal if futexes are actually available. Changing to use a futex would be an ABI change for targets currently not using it, because it affects the layout of the shared state used by std::promise and std::future. That probably needs coordination with target maintainers.
