No need to include windows.h twice
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index ffaa596..6fcbe75 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -23,7 +23,7 @@
 
 #ifdef MS_WINDOWS
 #define WIN32_LEAN_AND_MEAN
-#include "windows.h"
+#include <windows.h>
 #endif /* MS_WINDOWS */
 
 #ifdef MS_COREDLL
@@ -36,10 +36,6 @@
 #include <unixlib.h>
 #endif
 
-#ifdef MS_WINDOWS
-#include <windows.h>
-#endif
-
 #ifdef HAVE_LANGINFO_H
 #include <locale.h>
 #include <langinfo.h>