diff --git a/external/wepoll/wepoll.c b/external/wepoll/wepoll.c
--- a/external/wepoll/wepoll.c
+++ b/external/wepoll/wepoll.c
@@ -140,9 +140,9 @@
 #pragma warning(push, 1)
 #endif
 
-#include <WS2tcpip.h>
-#include <WinSock2.h>
-#include <Windows.h>
+#include <ws2tcpip.h>
+#include <winsock2.h>
+#include <windows.h>
 
 #ifndef __GNUC__
 #pragma warning(pop)
