diff --git a/configure.ac b/configure.ac
index f1da4f546365bf665994ef5f9f5a57ea729d067e..62439e1540544b00f871d3236c54f58fddfebc81 100644
--- a/configure.ac
+++ b/configure.ac
@@ -610,7 +610,6 @@ AC_CHECK_TYPES([struct pollfd],,,
 #if HAVE_POLL
 # include <poll.h>
 #elif defined (_WIN32)
-# define _WIN32_WINNT 0x502
 # include <winsock2.h>
 #endif
 ])