Native bindings to the KHR_wait_sync extension.

This extension adds the ability to wait for signaling of sync objects in the server for a client API context, rather than in the application thread bound to that context. This form of wait does not necessarily block the application thread which issued the wait (unlike eglClientWaitSyncKHR), so the application may continue to issue commands to the client API context or perform other work in parallel, leading to increased performance. The best performance is likely to be achieved by implementations which can perform this new wait operation in GPU hardware, although this is not required.

Requires EGL 1.1 and KHR_fence_sync.