diff --git a/include/vsb.h b/include/vsb.h
index d510884..d9820bf 100644
--- a/include/vsb.h
+++ b/include/vsb.h
@@ -28,6 +28,10 @@
  *      $FreeBSD: head/sys/sys/vsb.h 221993 2011-05-16 16:18:40Z phk $
  */
 
+#ifdef HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+
 #ifndef VSB_H_INCLUDED
 #define VSB_H_INCLUDED