diff --git a/library/net_sockets.c b/library/net_sockets.c
index f99d339..62f5b68 100644
--- a/library/net_sockets.c
+++ b/library/net_sockets.c
@@ -47,11 +47,12 @@
 
 #define IS_EINTR( ret ) ( ( ret ) == WSAEINTR )
 
-#ifdef _WIN32_WINNT
+#if !defined(_WIN32_WINNT) || (_WIN32_WINNT < 0x0501)
 #undef _WIN32_WINNT
-#endif
 /* Enables getaddrinfo() & Co */
 #define _WIN32_WINNT 0x0501
+#endif
+
 #include <ws2tcpip.h>
 
 #include <winsock2.h>