Merge branches/pep-0384.
diff --git a/Include/objimpl.h b/Include/objimpl.h
index 2980031..3fef376 100644
--- a/Include/objimpl.h
+++ b/Include/objimpl.h
@@ -246,6 +246,7 @@
 #define _PyObject_GC_Del PyObject_GC_Del
 
 /* GC information is stored BEFORE the object structure. */
+#ifndef Py_LIMITED_API
 typedef union _gc_head {
     struct {
         union _gc_head *gc_next;
@@ -298,7 +299,7 @@
 #define _PyObject_GC_MAY_BE_TRACKED(obj) \
     (PyObject_IS_GC(obj) && \
         (!PyTuple_CheckExact(obj) || _PyObject_GC_IS_TRACKED(obj)))
-
+#endif /* Py_LIMITED_API */
 
 PyAPI_FUNC(PyObject *) _PyObject_GC_Malloc(size_t);
 PyAPI_FUNC(PyObject *) _PyObject_GC_New(PyTypeObject *);