https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66146
--- Comment #11 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #4)
> Thanks, Martin. So maybe something like this:
>
> --- a/libstdc++-v3/include/std/mutex
> +++ b/libstdc++-v3/include/std/mutex
> @@ -726,7 +738,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> __set_once_functor_lock_ptr(&__functor_lock);
> #endif
>
> +#ifdef __powerpc__
> + int __e;
> + __try {
> + __e = __gthread_once(&__once._M_once, &__once_proxy);
> + } __catch(...) {
> + __once._M_once = once_flag{}._M_once;
N.B. This won't work because it races, and may not even compile (if e.g.
pthread_once_t has a const member)
