[Bug plugins/81283] Quirks around 32-bit PowerPC built-in Atomics

[kallisti5 at unixzen dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81283

--- Comment #1 from Alexander von Gluck <kallisti5 at unixzen dot com> ---
Here is some context on our wrapper for the atomic call generating the
__atomic_fetch_add_8 references.

static __inline__ void
atomic_set64(int64* value, int64 newValue)
{
        __atomic_store_n(value, newValue, __ATOMIC_RELEASE);
}