diff --git a/src/include/lwip/sockets.h b/src/include/lwip/sockets.h
index 7e8172cc..d5f8ccf7 100644
--- a/src/include/lwip/sockets.h
+++ b/src/include/lwip/sockets.h
@@ -209,7 +209,11 @@ struct linger {
  * only define this in sockets.c so it does not interfere
  * with other projects namespaces where timeval is present
  */ 
-#ifdef LWIP_TIMEVAL_PRIVATE
+#ifndef LWIP_TIMEVAL_PRIVATE
+#define LWIP_TIMEVAL_PRIVATE 1
+#endif
+
+#if LWIP_TIMEVAL_PRIVATE
   struct timeval {
     long    tv_sec;         /* seconds */
     long    tv_usec;        /* and microseconds */