Implement access control

Move send and dispatch functions to the implementation. This makes it
possible to place an access check before sending and dispatching.
Add module-access that allows to bind and notify on globals owned by
the client.

spa/include/spa/defs.h

@@ -67,6 +67,8 @@ typedef enum {
   SPA_RESULT_ASYNC_BUSY                = -30,
   SPA_RESULT_INVALID_OBJECT_ID         = -31,
   SPA_RESULT_NO_MEMORY                 = -32,
+  SPA_RESULT_NO_PERMISSION             = -33,
+  SPA_RESULT_SKIPPED                   = -34,
 } SpaResult;
 
 #define SPA_ASYNC_MASK                  (3 << 30)

spa/include/spa/meson.build

@@ -1,21 +1,21 @@
 spa_headers = [
+  'barrier.h',
   'buffer.h',
   'clock.h',
-  'control.h',
-  'debug.h',
   'defs.h',
   'dict.h',
   'format.h',
+  'id-map.h',
+  'list.h',
   'log.h',
+  'loop.h',
   'monitor.h',
   'node-command.h',
   'node-event.h',
   'node.h',
   'plugin.h',
-  'poll.h',
   'port.h',
   'props.h',
-  'queue.h',
   'ringbuffer.h'
 ]