--- lib/sfio/sftable.c
+++ lib/sfio/sftable.c
@@ -14,6 +14,8 @@
 *              AT&T Research, Florham Park NJ             *
 **********************************************************/
 
+#include <stddef.h>
+
 #include	"sfhdr.h"
 
 /*	Dealing with $ argument addressing stuffs.
--- lib/sfio/sfvprintf.c
+++ lib/sfio/sfvprintf.c
@@ -14,6 +14,7 @@
 *              AT&T Research, Florham Park NJ             *
 **********************************************************/
 
+#include <stddef.h>
 #include	"sfhdr.h"
 
 /*	The engine for formatting data
--- lib/sfio/sfvscanf.c
+++ lib/sfio/sfvscanf.c
@@ -14,6 +14,7 @@
 *              AT&T Research, Florham Park NJ             *
 **********************************************************/
 
+#include <stddef.h>
 #include	"sfhdr.h"
 
 /*	The main engine for reading formatted data