diff --git a/libraries/AP_Common/AP_Var.cpp b/libraries/AP_Common/AP_Var.cpp
index 4fc41e079c..c18ec215d5 100644
--- a/libraries/AP_Common/AP_Var.cpp
+++ b/libraries/AP_Common/AP_Var.cpp
@@ -11,5 +11,5 @@
 
 #include "AP_Var.h"
 
-extern AP_Int8 AP_unity(1);
-extern AP_Int8 AP_negativeUnity(-1);
+AP_Int8 AP_unity(1);
+AP_Int8 AP_negativeUnity(-1);