--- includes/arpa/nameser.h
+++ includes/arpa/nameser.h
@@ -61,6 +61,8 @@
 #ifndef _ARPA_NAMESER_H_
 #define _ARPA_NAMESER_H_
 
+#include <sys/types.h>
+
 /*
  * Revision information.  This is the release date in YYYYMMDD format.
  * It can change every day so the right thing to do with it is use it
