&mach_exception_handler_port_set);
	if (ret) {
		fprintf(stderr, "runtime/cgo: mach_port_allocate failed for port_set: %d\n", ret);
		abort();
	}

	// Block all signals to the exception handler thread
	sigfillset(&ign);
	pthread_sigmask(SIG_SETMASK, &ign, &oset);

	// Start a thread to handle exceptions.
	uintptr_t port_set = (uintptr_t)mach_exception_handler_port_set;
	pthread_attr_init(&attr);

	_sigev_max_size = 64
)

//go:nosplit
//go:nowritebarrierrec
func setsig(i uint32, fn uintptr) {
	var sa sigactiont
	sa.sa_flags = _SA_SIGINFO | _SA_ONSTACK | _SA_RESTORER | _SA_RESTART
	sigfillset(&sa.sa_mask)
	// Although Linux manpage says "sa_restorer element is obsolete and
	// should not be used". x86_64 kernel requires it. Only use it on
	// x86.
	if GOARCH == "386" || GOARCH == "amd64" {