MyGUI version guard.

apps/openmw/mwgui/layout.cpp

@@ -85,6 +85,7 @@ namespace MWGui
 
     void Layout::setLayerPick(bool pick)
     {
+#if MYGUI_VERSION >= MYGUI_DEFINE_VERSION(3,4,0)
         MyGUI::ILayer* layer = mMainWidget->getLayer();
         // MyGUI exposes pick on the implementations of ILayer only, but not ILayer itself.
         auto* oLayer = layer->castType<MyGUI::OverlappedLayer>(false);
@@ -93,6 +94,12 @@ namespace MWGui
             oLayer->setPick(pick);
         if (sLayer)
             sLayer->setPick(pick);
+#else
+#ifdef USE_OPENXR
+#error "MyGUI version 3.4.0 or greater required to build for VR"
+#endif
+        throw std::logic_error("Not implemented");
+#endif
     }
 
     MyGUI::Widget* Layout::getWidget(const std::string &_name)