Get ShowWindowModal behavior working under OS X Cocoa for file, dir and message dialogs.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63291 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/osx/msgdlg.h

@@ -23,6 +23,11 @@ public:
                     const wxPoint& pos = wxDefaultPosition);
 
     virtual int ShowModal();
+    
+#if wxOSX_USE_COCOA
+    virtual void ShowWindowModal();
+    virtual void ModalFinishedCallback(void* panel, int resultCode);
+#endif
 
 protected:
     // not supported for message dialog
@@ -30,6 +35,13 @@ protected:
                            int WXUNUSED(width), int WXUNUSED(height),
                            int WXUNUSED(sizeFlags) = wxSIZE_AUTO) {}
 
+#if wxOSX_USE_COCOA
+    void* ConstructNSAlert();
+#endif
+
+    int m_buttonId[3];
+    int m_buttonCount;
+
     DECLARE_DYNAMIC_CLASS(wxMessageDialog)
 };