Include <netinet/in.h>, which is necessary to get the code compiled

on FreeBSD.

resolve.h

@@ -43,6 +43,7 @@
 
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <netinet/in.h>
 #include <netdb.h>
 #include <arpa/nameser.h>
 #include <resolv.h>