If the goal is to have Darwin and Corelibs Foundation as API compatible as possible, I think the Foundation team at Apple should start introducing some of the rare API changes back into Darwin Foundation before the final release of iOS 10 and macOS Sierra.
For example, it's currently impossible to initialize a Thread object with the same code on both platforms. Darwin has a target+action initializer and Corelibs has a closure initializer. As Corelibs can not have the target+action initializer, the only solution is to have Darwin implement the closure initializer.
This is just one example and I guess they are more out there.
Comments? How do we proceed?