ipops: fix compilation under FreeBSD

- unable to compile detailed_ip_type.c under FreeBSD needs extra header

modules/ipops/detailed_ip_type.c

@@ -26,6 +26,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <arpa/inet.h>
+#if defined (__OS_freebsd)
+#include <sys/socket.h>
+#endif
 #include <string.h>
 #include <unistd.h>
 #include "../../dprint.h"