MINOR: sock: do not use LI_O_* in xfer_sock_list anymore

We'll want to store more info there and some info that are not represented
in listener options at the moment (such as dgram vs stream) so let's get
rid of these and instead use a new set of options (SOCK_XFER_OPT_*).
diff --git a/src/sock.c b/src/sock.c
index b8a729b..894f485 100644
--- a/src/sock.c
+++ b/src/sock.c
@@ -294,7 +294,7 @@
 
 		/* determine the foreign status directly from the socket itself */
 		if (sock_inet_is_foreign(fd, xfer_sock->addr.ss_family))
-			xfer_sock->options |= LI_O_FOREIGN;
+			xfer_sock->options |= SOCK_XFER_OPT_FOREIGN;
 
 #if defined(IPV6_V6ONLY)
 		/* keep only the v6only flag depending on what's currently
@@ -303,7 +303,7 @@
 		socklen = sizeof(val);
 		if (xfer_sock->addr.ss_family == AF_INET6 &&
 		    getsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &val, &socklen) == 0 && val > 0)
-			xfer_sock->options |= LI_O_V6ONLY;
+			xfer_sock->options |= SOCK_XFER_OPT_V6ONLY;
 #endif
 
 		xfer_sock->fd = fd;
@@ -354,7 +354,7 @@
 int sock_find_compatible_fd(const struct listener *l)
 {
 	struct xfer_sock_list *xfer_sock = xfer_sock_list;
-	int options = l->options & (LI_O_FOREIGN | LI_O_V6ONLY | LI_O_V4V6);
+	int options = 0;
 	int if_namelen = 0;
 	int ns_namelen = 0;
 	int ret = -1;
@@ -362,17 +362,18 @@
 	if (!l->proto->addrcmp)
 		return -1;
 
+	if (l->options & LI_O_FOREIGN)
+		options |= SOCK_XFER_OPT_FOREIGN;
+
 	if (l->addr.ss_family == AF_INET6) {
 		/* Prepare to match the v6only option against what we really want. Note
 		 * that sadly the two options are not exclusive to each other and that
 		 * v6only is stronger than v4v6.
 		 */
-		if ((options & LI_O_V6ONLY) || (sock_inet6_v6only_default && !(options & LI_O_V4V6)))
-			options |= LI_O_V6ONLY;
-		else if ((options & LI_O_V4V6) || !sock_inet6_v6only_default)
-			options &= ~LI_O_V6ONLY;
+		if ((l->options & LI_O_V6ONLY) ||
+		    (sock_inet6_v6only_default && !(l->options & LI_O_V4V6)))
+			options |= SOCK_XFER_OPT_V6ONLY;
 	}
-	options &= ~LI_O_V4V6;
 
 	if (l->interface)
 		if_namelen = strlen(l->interface);
@@ -382,7 +383,7 @@
 #endif
 
 	while (xfer_sock) {
-		if (((options ^ xfer_sock->options) & (LI_O_FOREIGN | LI_O_V6ONLY)) == 0 &&
+		if ((options == xfer_sock->options) &&
 		    (if_namelen == xfer_sock->if_namelen) &&
 		    (ns_namelen == xfer_sock->ns_namelen) &&
 		    (!if_namelen || strcmp(l->interface, xfer_sock->iface) == 0) &&