squashed warning around NS_STACK_SIZE

mongoose.c

@@ -147,6 +147,8 @@ union socket_address {
   struct sockaddr_in sin;
 #ifdef NS_ENABLE_IPV6
   struct sockaddr_in6 sin6;
+#else
+  struct sockaddr sin6;
 #endif
 };
 
@@ -338,7 +340,7 @@ void *ns_start_thread(void *(*f)(void *), void *p) {
   (void) pthread_attr_init(&attr);
   (void) pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 
-#if NS_STACK_SIZE > 1
+#if defined(NS_STACK_SIZE) && NS_STACK_SIZE > 1
   (void) pthread_attr_setstacksize(&attr, NS_STACK_SIZE);
 #endif
 
@@ -557,7 +559,7 @@ static sock_t ns_open_listening_socket(union socket_address *sa) {
       !setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *) &on, sizeof(on)) &&
 #endif
       !bind(sock, &sa->sa, sa->sa.sa_family == AF_INET ?
-            sizeof(sa->sin) : sizeof(sa->sa)) &&
+            sizeof(sa->sin) : sizeof(sa->sin6)) &&
       !listen(sock, SOMAXCONN)) {
     ns_set_non_blocking_mode(sock);
     // In case port was set to 0, get the real port number