diff --git a/libs/putty/network.h b/libs/putty/network.h
index ec7f7b4f6..0c519e364 100644
--- a/libs/putty/network.h
+++ b/libs/putty/network.h
@@ -227,9 +227,9 @@ SockAddr *sk_addr_dup(SockAddr *addr);
 
 /* NB, control of 'addr' is passed via sk_new, which takes responsibility
  * for freeing it, as for new_connection() */
-#if defined(__BORLANDC__)
+#if defined(sk_new)
 #undef sk_new
-#endif // defined(__BORLANDC__)
+#endif
 Socket *sk_new(SockAddr *addr, int port, bool privport, bool oobinline,
                bool nodelay, bool keepalive, Plug *p,
 #ifdef MPEXT