diff --git a/libraries/AP_HAL_AVR/memcheck.cpp b/libraries/AP_HAL_AVR/memcheck.cpp
index e64134df64..5ac4d6b58b 100644
--- a/libraries/AP_HAL_AVR/memcheck.cpp
+++ b/libraries/AP_HAL_AVR/memcheck.cpp
@@ -8,6 +8,7 @@
  *  of false positives with uninitialised stack variables
  */
 
+#include <AP_HAL.h>
 #include <stdlib.h>
 #include <stdint.h>