added a dummy return to GetItemState() to suppress gcc warning (but shouldn't we assert in all these functions if neither generic nor native implementation is used instead?)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43770 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/mac/carbon/listctrl_mac.cpp

@@ -1092,6 +1092,8 @@ int wxListCtrl::GetItemState(long item, long stateMask) const
             return info.m_state;
         }
     }
+
+    return 0;
 }
 
 // Sets the item state