var runtime.extraMWaiters

4 uses

	runtime (current package)
		cgocall.go#L245: 	if gp.m.needextram || atomic.Load(&extraMWaiters) > 0 {
		proc.go#L1877: 	c := atomic.Xchg(&extraMWaiters, 0)
		proc.go#L2000: var extraMWaiters uint32
		proc.go#L2023: 				atomic.Xadd(&extraMWaiters, 1)