EGL_EXT_client_sync
https://www.khronos.org/registry/egl/specs/eglspec.1.5.pdf
EGL_EXT_client_sync

	EGL_SYNC_CLIENT_EXT 0x3364
	EGL_SYNC_CLIENT_SIGNAL_EXT 0x3365
	EGLBoolean eglClientSignalSyncEXT (EGLDisplay dpy, EGLSync sync, const EGLAttrib* attrib_list)