Added part of patch

[ 1573619 ] Fix for Reentrance problems in events
  in slightly modified form.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41874 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/event.h

@@ -2398,7 +2398,6 @@ public:
     // add an event to be processed later
     void AddPendingEvent(wxEvent& event);
 
-    // process all pending events
     void ProcessPendingEvents();
 
 #if wxUSE_THREADS
@@ -2458,6 +2457,11 @@ public:
     void SetClientData( void *data ) { DoSetClientData(data); }
     void *GetClientData() const { return DoGetClientData(); }
 
+    // reentrance guard
+    void AllowReentrance( bool allow = true ) { m_reentranceAllowed = allow; }
+    bool IsReentranceAllowed()                { return m_reentranceAllowed; }
+    bool IsEventHandlingInProgress()          { return m_eventHandlingInProgress; } 
+    
     // check if the given event table entry matches this event and call the
     // handler if it does
     //
@@ -2527,6 +2531,9 @@ protected:
 #  endif
 #endif
 
+    bool                m_reentranceAllowed;          // Reentrance is allowed for this handler?
+    bool                m_eventHandlingInProgress;    // Eventhandling is in progress?
+    
     // Is event handler enabled?
     bool                m_enabled;