Fixed wxMenuItem::Enable.

Added unique IDs to all menus (using a new static member of wxMenu).
Use wxWindow's ID as menu item ID seen by OS/2.
Rewrote wxMenu::DoInsertOrAppend which now uses the MENUITEM of the
      submenu or menu item which already contains most of the needed
      informations (especially the ID!)


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_2_BRANCH@7238 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/os2/menu.h

@@ -154,6 +154,11 @@ private:
     //
     WXHMENU                         m_hMenu;
 
+    //
+    // The helper variable for creating unique IDs.
+    //
+    static USHORT		    m_nextMenuId;
+
 #if wxUSE_ACCEL
     //
     // The accelerators for our menu items