diff --git a/boards/px4/sitl/src/board_shutdown.cpp b/boards/px4/sitl/src/board_shutdown.cpp
index 464fdc83c1..eeb3e921b7 100644
--- a/boards/px4/sitl/src/board_shutdown.cpp
+++ b/boards/px4/sitl/src/board_shutdown.cpp
@@ -40,6 +40,7 @@
 #include <px4_platform_common/tasks.h>
 #include <board_config.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #if defined(BOARD_HAS_POWER_CONTROL)
 int board_register_power_state_notification_cb(power_button_state_notification_t cb)
diff --git a/platforms/nuttx/src/px4/common/board_crashdump.c b/platforms/nuttx/src/px4/common/board_crashdump.c
index 035bc60443..90e541ae0e 100644
--- a/platforms/nuttx/src/px4/common/board_crashdump.c
+++ b/platforms/nuttx/src/px4/common/board_crashdump.c
@@ -38,10 +38,10 @@
  * and hardfault log support
  */
 
-#ifdef CONFIG_BOARD_CRASHDUMP
-
 #include <board_config.h>
 
+#ifdef CONFIG_BOARD_CRASHDUMP
+
 #include <stdio.h>
 #include <stdbool.h>
 #include <string.h>
diff --git a/platforms/nuttx/src/px4/common/cdc_acm_check.cpp b/platforms/nuttx/src/px4/common/cdc_acm_check.cpp
index 5d9702152f..14c0b560b6 100644
--- a/platforms/nuttx/src/px4/common/cdc_acm_check.cpp
+++ b/platforms/nuttx/src/px4/common/cdc_acm_check.cpp
@@ -31,6 +31,8 @@
  *
  ****************************************************************************/
 
+#include <board_config.h>
+
 #if defined(CONFIG_SYSTEM_CDCACM)
 __BEGIN_DECLS
 #include <arch/board/board.h>
diff --git a/platforms/nuttx/src/px4/stm/stm32f7/include/px4_arch/spi_hw_description.h b/platforms/nuttx/src/px4/stm/stm32f7/include/px4_arch/spi_hw_description.h
index 702635fdb4..f077fc7050 100644
--- a/platforms/nuttx/src/px4/stm/stm32f7/include/px4_arch/spi_hw_description.h
+++ b/platforms/nuttx/src/px4/stm/stm32f7/include/px4_arch/spi_hw_description.h
@@ -32,6 +32,8 @@
  ****************************************************************************/
 #pragma once
 
+#include <board_config.h>
+
 #if defined(CONFIG_SPI)
 
 #include "../../../stm32_common/include/px4_arch/spi_hw_description.h"
diff --git a/platforms/posix/src/px4/common/lockstep_scheduler/include/lockstep_scheduler/lockstep_scheduler.h b/platforms/posix/src/px4/common/lockstep_scheduler/include/lockstep_scheduler/lockstep_scheduler.h
index 2e5a1eaab5..05cf64665a 100644
--- a/platforms/posix/src/px4/common/lockstep_scheduler/include/lockstep_scheduler/lockstep_scheduler.h
+++ b/platforms/posix/src/px4/common/lockstep_scheduler/include/lockstep_scheduler/lockstep_scheduler.h
@@ -39,6 +39,7 @@
 #include <memory>
 #include <atomic>
 #include <pthread.h>
+#include <unistd.h>
 
 #include "lockstep_components.h"
 
diff --git a/src/drivers/imu/invensense/icm20602/InvenSense_ICM20602_registers.hpp b/src/drivers/imu/invensense/icm20602/InvenSense_ICM20602_registers.hpp
index 682539fe33..7ef5af0494 100644
--- a/src/drivers/imu/invensense/icm20602/InvenSense_ICM20602_registers.hpp
+++ b/src/drivers/imu/invensense/icm20602/InvenSense_ICM20602_registers.hpp
@@ -41,6 +41,7 @@
 #pragma once
 
 #include <cstdint>
+#include <cstddef>
 
 // TODO: move to a central header
 static constexpr uint8_t Bit0 = (1 << 0);
diff --git a/src/drivers/imu/invensense/icm20689/InvenSense_ICM20689_registers.hpp b/src/drivers/imu/invensense/icm20689/InvenSense_ICM20689_registers.hpp
index 11999e9aeb..754812d3ea 100644
--- a/src/drivers/imu/invensense/icm20689/InvenSense_ICM20689_registers.hpp
+++ b/src/drivers/imu/invensense/icm20689/InvenSense_ICM20689_registers.hpp
@@ -41,6 +41,7 @@
 #pragma once
 
 #include <cstdint>
+#include <cstddef>
 
 // TODO: move to a central header
 static constexpr uint8_t Bit0 = (1 << 0);
diff --git a/src/drivers/imu/invensense/icm20948/InvenSense_ICM20948_registers.hpp b/src/drivers/imu/invensense/icm20948/InvenSense_ICM20948_registers.hpp
index 12fcbdbd62..827b2351d4 100644
--- a/src/drivers/imu/invensense/icm20948/InvenSense_ICM20948_registers.hpp
+++ b/src/drivers/imu/invensense/icm20948/InvenSense_ICM20948_registers.hpp
@@ -41,6 +41,7 @@
 #pragma once
 
 #include <cstdint>
+#include <cstddef>
 
 namespace InvenSense_ICM20948
 {
diff --git a/src/drivers/imu/invensense/icm42688p/InvenSense_ICM42688P_registers.hpp b/src/drivers/imu/invensense/icm42688p/InvenSense_ICM42688P_registers.hpp
index bf44666a01..b8d9260a49 100644
--- a/src/drivers/imu/invensense/icm42688p/InvenSense_ICM42688P_registers.hpp
+++ b/src/drivers/imu/invensense/icm42688p/InvenSense_ICM42688P_registers.hpp
@@ -41,6 +41,7 @@
 #pragma once
 
 #include <cstdint>
+#include <cstddef>
 
 namespace InvenSense_ICM42688P
 {
diff --git a/src/include/containers/Bitset.hpp b/src/include/containers/Bitset.hpp
index 8098554b93..aeeeab0cad 100644
--- a/src/include/containers/Bitset.hpp
+++ b/src/include/containers/Bitset.hpp
@@ -34,6 +34,7 @@
 #pragma once
 
 #include <stdint.h>
+#include <stddef.h>
 
 namespace px4
 {
diff --git a/src/lib/cdev/posix/cdev_platform.cpp b/src/lib/cdev/posix/cdev_platform.cpp
index 16a956b673..0a977a1bba 100644
--- a/src/lib/cdev/posix/cdev_platform.cpp
+++ b/src/lib/cdev/posix/cdev_platform.cpp
@@ -40,6 +40,8 @@
 #include <px4_platform_common/posix.h>
 #include <px4_platform_common/time.h>
 
+#include <stdlib.h>
+
 const cdev::px4_file_operations_t cdev::CDev::fops = {};
 
 pthread_mutex_t devmutex = PTHREAD_MUTEX_INITIALIZER;
diff --git a/src/modules/dataman/dataman.cpp b/src/modules/dataman/dataman.cpp
index 220471db01..42d6d41432 100644
--- a/src/modules/dataman/dataman.cpp
+++ b/src/modules/dataman/dataman.cpp
@@ -50,6 +50,7 @@
 #include <drivers/drv_hrt.h>
 #include <lib/parameters/param.h>
 #include <lib/perf/perf_counter.h>
+#include <stdlib.h>
 
 #include "dataman.h"
 
diff --git a/src/systemcmds/gpio/gpio.cpp b/src/systemcmds/gpio/gpio.cpp
index 0b1458f9b6..343c1bbd18 100644
--- a/src/systemcmds/gpio/gpio.cpp
+++ b/src/systemcmds/gpio/gpio.cpp
@@ -42,6 +42,8 @@
 #include <px4_platform_common/module.h>
 #include <px4_platform_common/px4_config.h>
 
+#include <stdlib.h>
+
 #include <nuttx/ioexpander/gpio.h>
 #include <fcntl.h>
 
diff --git a/src/systemcmds/i2cdetect/i2cdetect.cpp b/src/systemcmds/i2cdetect/i2cdetect.cpp
index f02f3570e3..cf2ce1290a 100644
--- a/src/systemcmds/i2cdetect/i2cdetect.cpp
+++ b/src/systemcmds/i2cdetect/i2cdetect.cpp
@@ -43,6 +43,8 @@
 #include <px4_platform_common/module.h>
 #include <px4_platform_common/getopt.h>
 
+#include <stdlib.h>
+
 namespace i2cdetect
 {
 
diff --git a/src/systemcmds/system_time/system_time.cpp b/src/systemcmds/system_time/system_time.cpp
index 4d4b2d8feb..e98e09b5a1 100644
--- a/src/systemcmds/system_time/system_time.cpp
+++ b/src/systemcmds/system_time/system_time.cpp
@@ -34,6 +34,8 @@
 #include <px4_platform_common/module.h>
 #include <px4_platform_common/time.h>
 
+#include <stdlib.h>
+
 using namespace time_literals;
 
 static void	usage();