diff --git a/extern/Eigen2/Eigen/src/Core/util/Memory.h b/extern/Eigen2/Eigen/src/Core/util/Memory.h
index 0a43e7f7bf2..8ff8d87c55c 100644
--- a/extern/Eigen2/Eigen/src/Core/util/Memory.h
+++ b/extern/Eigen2/Eigen/src/Core/util/Memory.h
@@ -37,6 +37,8 @@
 #define EIGEN_FREEBSD_MALLOC_ALREADY_ALIGNED 0
 #endif
 
+#include <stddef.h>
+
 #if defined(__APPLE__) || defined(_WIN64) || EIGEN_FREEBSD_MALLOC_ALREADY_ALIGNED
   #define EIGEN_MALLOC_ALREADY_ALIGNED 1
 #else
diff --git a/intern/ghost/GHOST_IEvent.h b/intern/ghost/GHOST_IEvent.h
index 4c8c4d4a392..bb13179fbfe 100644
--- a/intern/ghost/GHOST_IEvent.h
+++ b/intern/ghost/GHOST_IEvent.h
@@ -34,6 +34,7 @@
 #ifndef _GHOST_IEVENT_H_
 #define _GHOST_IEVENT_H_
 
+#include <stddef.h>
 #include "GHOST_Types.h"
 
 class GHOST_IWindow;
diff --git a/intern/memutil/MEM_Allocator.h b/intern/memutil/MEM_Allocator.h
index 9e9ce47c84f..14d62a2434d 100644
--- a/intern/memutil/MEM_Allocator.h
+++ b/intern/memutil/MEM_Allocator.h
@@ -29,6 +29,7 @@
 #ifndef MEM_ALLOCATOR_H
 #define MEM_ALLOCATOR_H
 
+#include <stddef.h>
 #include "guardedalloc/MEM_guardedalloc.h"
 #include "guardedalloc/MEM_sys_types.h"
 
diff --git a/source/gameengine/Converter/BL_ArmatureChannel.cpp b/source/gameengine/Converter/BL_ArmatureChannel.cpp
index 626d8a19deb..df3a575850b 100644
--- a/source/gameengine/Converter/BL_ArmatureChannel.cpp
+++ b/source/gameengine/Converter/BL_ArmatureChannel.cpp
@@ -37,6 +37,7 @@
 #include "BL_ArmatureConstraint.h"
 #include "BLI_math.h"
 #include "BLI_string.h"
+#include <stddef.h>
 
 #ifdef WITH_PYTHON
 
diff --git a/source/gameengine/Expressions/PyObjectPlus.h b/source/gameengine/Expressions/PyObjectPlus.h
index 7d06cc64ee9..157124ebc81 100644
--- a/source/gameengine/Expressions/PyObjectPlus.h
+++ b/source/gameengine/Expressions/PyObjectPlus.h
@@ -45,6 +45,7 @@
 #include "STR_String.h"
 #include "MT_Vector3.h"
 #include "SG_QList.h"
+#include <stddef.h>
 
 /*------------------------------
  * Python defines