diff --git a/src/runtime/python/ffi.h b/src/runtime/python/ffi.h
index 50325fcfb..07dea8dba 100644
--- a/src/runtime/python/ffi.h
+++ b/src/runtime/python/ffi.h
@@ -38,4 +38,8 @@ void FreePgfPrintContext(PgfPrintContext *ctxt);
 extern PgfUnmarshaller unmarshaller;
 extern PgfMarshaller marshaller;
 
+#if defined(_MSC_VER)
+#define alloca _alloca
+#endif
+
 #endif // PYPGF_FFI_H_