Add support for SO_REUSEPORT. This is also a workaround for libevent'…

…s current lack of support for this sockopt.

tcp_request.c

@@ -401,10 +401,19 @@ tcp_listener_bind(struct context *c)
# define LEV_OPT_DEFERRED_ACCEPT 0
#endif

    /* Until libevent gets support for SO_REUSEPORT we have to break
     * evconnlistener_new_bind() into a series of:
     * socket(), tcp_tune(), bind(), evconnlistener_new() */
    evutil_socket_t fd;
    fd = socket(c->local_sockaddr.ss_family, SOCK_STREAM, IPPROTO_TCP);
    
    tcp_tune(fd);
    evutil_make_socket_nonblocking(fd);

    if (bind(fd, (struct sockaddr *) &c->local_sockaddr, c->local_sockaddr_len) < 0) {
        logger(LOG_ERR, "Unable to bind (TCP): %s");
        return -1;
    }

    c->tcp_conn_listener =
        evconnlistener_new(c->event_loop,
@@ -416,7 +425,7 @@ tcp_listener_bind(struct context *c)
                                TCP_REQUEST_BACKLOG,
                                fd);
    if (c->tcp_conn_listener == NULL) {
        logger(LOG_ERR, "Unable to bind (TCP)");
        logger(LOG_ERR, "Unable to create listener (TCP)");
        return -1;
    }
    if (evconnlistener_disable(c->tcp_conn_listener) != 0) {