wxDFB: fix events processing to support sockets events

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43999 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/dfb/evtloop.h

@@ -31,6 +31,10 @@ public:
     // returns DirectFB event buffer used by wx
     static wxIDirectFBEventBufferPtr GetDirectFBEventBuffer();
 
+    // wxYield implementation: iterate the loop as long as there are any
+    // pending events
+    void Yield();
+
 protected:
     virtual void WakeUp();
     virtual void OnNextIteration();