08_refactor-makesock.diff

This is a refactoring of makesock():
 * the ubiquitous AF_UNSPEC is promoted as the default;
 * a wrapper for active sockets, para_connect_simple();
 * para_listen() now supports flowopts;
 * a wrapper for passive sockets, para_listen_simple();
 * for consistency, port numbers (which are 2 byte in
   UDP, TCP, and DCCP) have all been set to 'uint16_t'.