added HAVE_IOCTLSOCKET here
diff --git a/lib/config-win32.h b/lib/config-win32.h
index d666589..771f65d 100644
--- a/lib/config-win32.h
+++ b/lib/config-win32.h
@@ -217,6 +217,9 @@
/* Define this to if in_addr_t is not an available typedefed type */
#define in_addr_t unsigned long
+/* use ioctlsocket() for non-blocking sockets */
+#define HAVE_IOCTLSOCKET
+
/*************************************************
* This section is for compiler specific defines.*
*************************************************/