diff --git a/net/sock.c b/net/sock.c
index 7c32eb8..1715225 100644
--- a/net/sock.c
+++ b/net/sock.c
@@ -52,6 +52,7 @@
 #define EWOULDBLOCK WSAEWOULDBLOCK
 #define EALREADY WSAEALREADY
 #define socklen_t    int
+#define va_copy(ap1, ap2) ((ap1) = (ap2))
 #endif
 
 #include "sock.h"