diff --git a/dtool/src/parser-inc/windows.h b/dtool/src/parser-inc/windows.h
index 183421352f..319abf1892 100644
--- a/dtool/src/parser-inc/windows.h
+++ b/dtool/src/parser-inc/windows.h
@@ -30,3 +30,5 @@ typedef long DWORD;
 union LARGE_INTEGER {
   __int64 QuadPart;
 };
+
+#endif