bpo-36097: Use only public C-API in the_xxsubinterpreters module (adding as necessary). (#12003)

diff --git a/Include/interpreteridobject.h b/Include/interpreteridobject.h
new file mode 100644
index 0000000..e744fcd
--- /dev/null
+++ b/Include/interpreteridobject.h
@@ -0,0 +1,17 @@
+#ifndef Py_INTERPRETERIDOBJECT_H
+#define Py_INTERPRETERIDOBJECT_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef Py_LIMITED_API
+#  define Py_CPYTHON_INTERPRETERIDOBJECT_H
+#  include  "cpython/interpreteridobject.h"
+#  undef Py_CPYTHON_INTERPRETERIDOBJECT_H
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_INTERPRETERIDOBJECT_H */