Add missing wxUSE_MENUS checks to generic MDI classes

Make mdig.cpp compile with wxUSE_MENUS==0, as it already had many
wxUSE_MENUS checks and only missed a few more of them.

See #9626.

include/wx/generic/mdig.h

@@ -199,7 +199,9 @@ protected:
     void Init();
 
 private:
+#if wxUSE_MENUS
     void OnMenuHighlight(wxMenuEvent& event);
+#endif // wxUSE_MENUS
     void OnClose(wxCloseEvent& event);
 
     wxDECLARE_DYNAMIC_CLASS(wxGenericMDIChildFrame);

src/generic/mdig.cpp

@@ -382,7 +382,9 @@ bool wxGenericMDIParentFrame::ProcessEvent(wxEvent& event)
 wxIMPLEMENT_DYNAMIC_CLASS(wxGenericMDIChildFrame, wxFrame);
 
 wxBEGIN_EVENT_TABLE(wxGenericMDIChildFrame, wxFrame)
+#if wxUSE_MENUS
     EVT_MENU_HIGHLIGHT_ALL(wxGenericMDIChildFrame::OnMenuHighlight)
+#endif // wxUSE_MENUS
 
     EVT_CLOSE(wxGenericMDIChildFrame::OnClose)
 wxEND_EVENT_TABLE()
@@ -493,6 +495,7 @@ void wxGenericMDIChildFrame::Activate()
     parent->WXActivateChild(this);
 }
 
+#if wxUSE_MENUS
 void wxGenericMDIChildFrame::OnMenuHighlight(wxMenuEvent& event)
 {
     wxGenericMDIParentFrame * const parent = GetGenericMDIParent();
@@ -503,6 +506,7 @@ void wxGenericMDIChildFrame::OnMenuHighlight(wxMenuEvent& event)
         parent->OnMenuHighlight(event);
     }
 }
+#endif // wxUSE_MENUS
 
 void wxGenericMDIChildFrame::OnClose(wxCloseEvent& WXUNUSED(event))
 {