make sure we can issue a WakeUp call that really triggers at the NSRunLoop level not only only CFRunLoop

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@68301 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/osx/cocoa/evtloop.h

@@ -21,6 +21,8 @@ public:
     
     void EndModalSession();
 
+    virtual void WakeUp();
+
 protected:
     virtual int DoDispatchTimeout(unsigned long timeout);