adding empty base class implementation for OnNextIteration, call from OSXDoRun, allowing console event loop to override

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76223 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/osx/core/evtloop.h

@@ -55,6 +55,10 @@ protected:
     // terminating when Exit() is called
     virtual int DoRun();
 
+    // may be overridden to perform some action at the start of each new event
+    // loop iteration
+    virtual void OnNextIteration() {}
+
     virtual void DoYieldFor(long eventsToProcess);
 
     void CommonModeObserverCallBack(CFRunLoopObserverRef observer, int activity);