diff --git a/include/ac/socket.h b/include/ac/socket.h
index 70e044aa47..573601ea60 100644
--- a/include/ac/socket.h
+++ b/include/ac/socket.h
@@ -21,6 +21,8 @@
 
 #ifdef HAVE_WINSOCK2
 #include <winsock2.h>
+#define EMSGSIZE WSAEMSGSIZE
+#define EHOSTUNREACH WSAEHOSTUNREACH
 #elif HAVE_WINSOCK
 #include <winsock.h>
 #endif