Add UAVCAN_NO_GLOBAL_DATA_TYPE_REGISTRY flag to allow the global data type registry to be disabled

libuavcan/include/uavcan/node/global_data_type_registry.hpp

@@ -187,6 +187,7 @@ struct UAVCAN_EXPORT DefaultDataTypeRegistrator
 {
     DefaultDataTypeRegistrator()
     {
+#if !UAVCAN_NO_GLOBAL_DATA_TYPE_REGISTRY
         const GlobalDataTypeRegistry::RegistrationResult res =
             GlobalDataTypeRegistry::instance().registerDataType<Type>(Type::DefaultDataTypeID);
 
@@ -194,6 +195,7 @@ struct UAVCAN_EXPORT DefaultDataTypeRegistrator
         {
             handleFatalError("Type reg failed");
         }
+#endif
     }
 };