master
Introduce an implementation of nsync's internal semaphore that uses MacOS Grand Central Dispatch primitives. For documentation of that primitive, see: https://developer.apple.com/documentation/dispatch/1452955-dispatch_semaphore_create https://developer.apple.com/documentation/dispatch/1453087-dispatch_semaphore_wait https://developer.apple.com/documentation/dispatch/1452919-dispatch_semaphore_signal