diff --git a/src/modules/mavlink/mavlink_receiver.cpp b/src/modules/mavlink/mavlink_receiver.cpp
index 459473d436..3ac659608a 100644
--- a/src/modules/mavlink/mavlink_receiver.cpp
+++ b/src/modules/mavlink/mavlink_receiver.cpp
@@ -44,6 +44,7 @@
 #include <px4_config.h>
 #include <px4_time.h>
 #include <px4_tasks.h>
+#include <px4_defines.h>
 #include <unistd.h>
 #include <pthread.h>
 #include <stdio.h>
diff --git a/src/modules/muorb/krait/uORBKraitFastRpcChannel.cpp b/src/modules/muorb/krait/uORBKraitFastRpcChannel.cpp
index 736bb3eefe..71d052b4c6 100644
--- a/src/modules/muorb/krait/uORBKraitFastRpcChannel.cpp
+++ b/src/modules/muorb/krait/uORBKraitFastRpcChannel.cpp
@@ -36,9 +36,6 @@
 #include "px4_tasks.h"
 #include <drivers/drv_hrt.h>
 #include <cstdio>
-#ifdef __PX4_LINUX
-#define _GNU_SOURCE
-#endif
 #include <pthread.h>
 
 #define LOG_TAG "uORBKraitFastRpcChannel.cpp"
diff --git a/src/modules/simulator/simulator_mavlink.cpp b/src/modules/simulator/simulator_mavlink.cpp
index c2f7aa2f47..be4be9711e 100644
--- a/src/modules/simulator/simulator_mavlink.cpp
+++ b/src/modules/simulator/simulator_mavlink.cpp
@@ -39,9 +39,6 @@
 #include <drivers/drv_pwm_output.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
-#ifdef __PX4_LINUX
-#define _GNU_SOURCE
-#endif
 #include <pthread.h>
 
 extern "C" __EXPORT hrt_abstime hrt_reset(void);