Start on ShowWindowModal for OS X Cocoa. Not working properly as children do not display.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63232 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/osx/dialog.h

@@ -55,6 +55,8 @@ public:
 
     // For now, same as Show(TRUE) but returns return code
     virtual int ShowModal();
+    
+    virtual void ShowWindowModal();
 
     // may be called to terminate the dialog with the given return code
     virtual void EndModal(int retCode);
@@ -69,6 +71,9 @@ protected:
     // mac also takes command-period as cancel
     virtual bool IsEscapeKey(const wxKeyEvent& event);
 
+    // needed for cleanup on the Cocoa side.
+    void EndWindowModal();
+
 private:
     void Init();