diff --git a/libraries/GCS_MAVLink/GCS_MAVLink.h b/libraries/GCS_MAVLink/GCS_MAVLink.h
index 6e85053094..c256d4c05a 100644
--- a/libraries/GCS_MAVLink/GCS_MAVLink.h
+++ b/libraries/GCS_MAVLink/GCS_MAVLink.h
@@ -12,7 +12,7 @@
 // to select MAVLink 1.0 in the arduino GUI build
 //#define MAVLINK_SEPARATE_HELPERS
 
-#ifdef MAVLINK10
+#if MAVLINK10 == ENABLED
 # include "include/mavlink/v1.0/ardupilotmega/version.h"
 #else
 # include "include/mavlink/v0.9/ardupilotmega/version.h"
@@ -22,7 +22,7 @@
 #define MAVLINK_MAX_PAYLOAD_LEN MAVLINK_MAX_DIALECT_PAYLOAD_SIZE
 
 #define MAVLINK_COMM_NUM_BUFFERS 2
-#ifdef MAVLINK10
+#if MAVLINK10==ENABLED
 # include "include/mavlink/v1.0/mavlink_types.h"
 #else
 # include "include/mavlink/v0.9/mavlink_types.h"
@@ -119,7 +119,7 @@ static inline int comm_get_txspace(mavlink_channel_t chan)
 }
 
 #define MAVLINK_USE_CONVENIENCE_FUNCTIONS
-#ifdef MAVLINK10
+#if MAVLINK10==1
 # include "include/mavlink/v1.0/ardupilotmega/mavlink.h"
 #else
 # include "include/mavlink/v0.9/ardupilotmega/mavlink.h"
diff --git a/libraries/GCS_MAVLink/Mavlink_compat.h b/libraries/GCS_MAVLink/Mavlink_compat.h
index c159da8d93..10826b6a3c 100644
--- a/libraries/GCS_MAVLink/Mavlink_compat.h
+++ b/libraries/GCS_MAVLink/Mavlink_compat.h
@@ -2,7 +2,7 @@
   compatibility header during transition to MAVLink 1.0
  */
 
-#ifdef MAVLINK10
+#if MAVLINK10==1
 // in MAVLink 1.0 'waypoint' becomes 'mission'. We can remove these
 // mappings once we are not trying to support both protocols