diff --git a/Tools/ardupilotwaf/ardupilotwaf.py b/Tools/ardupilotwaf/ardupilotwaf.py
index b9ee486e90..ff755256e7 100644
--- a/Tools/ardupilotwaf/ardupilotwaf.py
+++ b/Tools/ardupilotwaf/ardupilotwaf.py
@@ -74,6 +74,7 @@ COMMON_VEHICLE_DEPENDENT_LIBRARIES = [
     'AP_ROMFS',
     'AP_Proximity',
     'AP_Gripper',
+    'AP_RTC',
 ]
 
 def get_legacy_defines(sketch_name):