--- ipv6calc.h.in.orig	Wed Feb 27 09:51:19 2002
+++ ipv6calc.h.in	Wed Feb 27 09:50:48 2002
@@ -19,6 +19,7 @@
 #define PROGRAM_COPYRIGHT "(P) & (C) 2001-2002 by Peter Bieringer <pb (at) bieringer.de>\n published under GNU GPL"
 
 /* global includes */
+#include <sys/types.h>
 #include <netinet/in.h>
 
 /*** global definitions ***/