diff --git a/lib/config-win32.h b/lib/config-win32.h
index b0f4f9e0df..5e9e8057c1 100644
--- a/lib/config-win32.h
+++ b/lib/config-win32.h
@@ -232,6 +232,9 @@
 /* use ioctlsocket() for non-blocking sockets */
 #define HAVE_IOCTLSOCKET
 
+/* Define this if you have struct sockaddr_storage */
+#define HAVE_STRUCT_SOCKADDR_STORAGE
+
 /* lber dynamic library file */
 /* #undef DL_LBER_FILE */