[master] include sys/socket.h for AF_INET/AF_INET6

Noticed on FreeBSD, but doing unconditionally.

We have this in other code for same reason.

src/lib/acl/ip_check.h

@@ -23,6 +23,7 @@
 
 #include <stdint.h>
 #include <arpa/inet.h>
+#include <sys/socket.h> // for AF_INET/AF_INET6
 #include <netinet/in.h>
 
 #include <acl/check.h>