diff --git a/Modules/getbuildinfo.c b/Modules/getbuildinfo.c
index dddcdeffd4aa94..8d553d106c6ab5 100644
--- a/Modules/getbuildinfo.c
+++ b/Modules/getbuildinfo.c
@@ -1,3 +1,7 @@
+#ifndef Py_BUILD_CORE_BUILTIN
+#  define Py_BUILD_CORE_MODULE 1
+#endif
+
 #include "Python.h"
 #include "pycore_pylifecycle.h"   // _Py_gitidentifier()