diff --git a/src/aclients.c b/src/aclients.c
index b8b2abd..0d0c3e7 100644
--- a/src/aclients.c
+++ b/src/aclients.c
@@ -76,6 +76,7 @@
 #include <stdio.h>
 #include <assert.h>
 #include <ctype.h>
+#include <stddef.h>
 #include <string.h>
 #include <time.h>
 
diff --git a/src/dwgpsd.c b/src/dwgpsd.c
index 6326704..890dd50 100644
--- a/src/dwgpsd.c
+++ b/src/dwgpsd.c
@@ -45,6 +45,7 @@
 #include <errno.h>
 #include <time.h>
 #include <math.h>
+#include <stddef.h>
 
 #if __WIN32__
 #error Not for Windows
diff --git a/src/dwgpsnmea.c b/src/dwgpsnmea.c
index 99209f3..840ab65 100644
--- a/src/dwgpsnmea.c
+++ b/src/dwgpsnmea.c
@@ -54,6 +54,7 @@
 #include <string.h>
 #include <errno.h>
 #include <time.h>
+#include <stddef.h>
 
 
 #include "textcolor.h"
diff --git a/src/kissnet.c b/src/kissnet.c
index 9588347..7b4f1c4 100644
--- a/src/kissnet.c
+++ b/src/kissnet.c
@@ -113,6 +113,7 @@
 #include <stdio.h>
 #include <assert.h>
 #include <string.h>
+#include <stddef.h>
 
 
 #include "tq.h"
diff --git a/src/kissutil.c b/src/kissutil.c
index 6fabc4a..026a6ea 100644
--- a/src/kissutil.c
+++ b/src/kissutil.c
@@ -56,6 +56,7 @@
 #include <stdio.h>
 #include <assert.h>
 #include <ctype.h>
+#include <stddef.h>
 #include <string.h>
 #include <getopt.h>
 #include <dirent.h>
diff --git a/src/recv.c b/src/recv.c
index 491ea40..a68ea38 100644
--- a/src/recv.c
+++ b/src/recv.c
@@ -88,6 +88,7 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stddef.h>
 #include <sys/types.h>
 //#include <sys/stat.h>
 //#include <sys/ioctl.h>
diff --git a/src/server.c b/src/server.c
index 6726a91..7acec09 100644
--- a/src/server.c
+++ b/src/server.c
@@ -145,6 +145,7 @@
 #include <string.h>
 #include <time.h>
 #include <ctype.h>
+#include <stddef.h>
 
 #include "tq.h"
 #include "ax25_pad.h"
diff --git a/src/xmit.c b/src/xmit.c
index e70e8b4..618b367 100644
--- a/src/xmit.c
+++ b/src/xmit.c
@@ -60,6 +60,7 @@
 #include <string.h>
 #include <math.h>
 #include <errno.h>
+#include <stddef.h>
 
 #include "direwolf.h"
 #include "ax25_pad.h"