synthesize declarations of missing observer types

Author: dgrove-oss

src/inline_internal.h

@@ -513,6 +513,18 @@ _dispatch_queue_get_bound_thread(dispatch_queue_t dq)
 	return dq->dq_thread;
 }
 
+#if __LINUX_PORT_HDD__
+// START HACK: DAVE.  These types are not defined anywhere in libdispatch sources,
+//                     so make something plausible up...
+typedef struct dispatch_pthread_root_queue_observer_hooks_s {
+    void (*queue_will_execute)(dispatch_queue_t);
+    void (*queue_did_execute)(dispatch_queue_t);
+} dispatch_pthread_root_queue_observer_hooks_s;
+
+typedef struct dispatch_pthread_root_queue_observer_hooks_s *
+    dispatch_pthread_root_queue_observer_hooks_t;
+#endif
+
 DISPATCH_ALWAYS_INLINE
 static inline dispatch_pthread_root_queue_observer_hooks_t
 _dispatch_get_pthread_root_queue_observer_hooks(void)