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

libuavcan/include/uavcan/build_config.hpp

@@ -100,6 +100,13 @@
 # define UAVCAN_TINY 0
 #endif
 
+/**
+ * Disable the global data type registry, which can save some space on embedded systems.
+ */
+#ifndef UAVCAN_NO_GLOBAL_DATA_TYPE_REGISTRY
+# define UAVCAN_NO_GLOBAL_DATA_TYPE_REGISTRY 1
+#endif
+
 /**
  * toString() methods will be disabled by default, unless the library is built for a general-purpose target like Linux.
  * It is not recommended to enable toString() on embedded targets as code size will explode.

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
     }
 };