diff --git a/include/ac/socket.h b/include/ac/socket.h
index 384a80aa3b..8522f76f90 100644
--- a/include/ac/socket.h
+++ b/include/ac/socket.h
@@ -101,6 +101,7 @@
 
 #undef	sock_errno
 #undef	sock_errstr
+#undef	sock_errset
 #define	sock_errno()	WSAGetLastError()
 #define	sock_errstr(e)	ber_pvt_wsa_err2string(e)
 #define	sock_errset(e)	WSASetLastError(e)