While we have always licked glibc and musl libc on gnu/systemd sadly the
Apple Libc implementation of pthread_mutex_t is better than ours. It may
be due to how the XNU kernel and M2 microprocessor are in league when it
comes to scheduling processes and the NSYNC behavior is being penalized.
We can solve this by leaning more heavily on ulock using Drepper's algo.
It's kind of ironic that Linux's official mutexes work terribly on Linux
but almost as good as Apple Libc if used on MacOS.
This change implements the compiler runtime for ARM v8.1 ISE atomics and
gets rid of the mandatory -mno-outline-atomics flag. It can dramatically
speed things up, on newer ARM CPUs, as indicated by the changed lines in
test/libc/thread/footek_test.c. In llamafile dispatching on hwcap atomic
also shaved microseconds off synchronization barriers.
- NetBSD should now have faster synchronization
- POSIX barriers may now be shared across processes
- An edge case with memory map tracking has been fixed
- Grand Central Dispatch is no longer used on MacOS ARM64
- POSIX mutexes in normal mode now use futexes across processes
