diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 3e5ecfe..96602ff 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -4,6 +4,7 @@
 #include "Python.h"
 
 #include "Python-ast.h"
+#undef Yield /* undefine macro conflicting with winbase.h */
 #include "grammar.h"
 #include "node.h"
 #include "token.h"