Use RIAA wrapper for wxSpinCtrl event disabling in wxGTK.

The use of wxSpinCtrlEventDisabler class ensures that we never forget to
reenable the events after disabling them.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74633 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/spinctrl.h

@@ -79,6 +79,8 @@ protected:
     // override this and return true.
     virtual bool UseGTKStyleBase() const { return true; }
 
+    friend class wxSpinCtrlEventDisabler;
+
     DECLARE_EVENT_TABLE()
 };