Partially revert commit
1a6be91e6fd65ce9cb88cbbbb193db7e92ec6076,
move back PyGC API from the internal API to the C API:
* _PyGCHead_NEXT(g), _PyGCHead_SET_NEXT(g, p)
* _PyGCHead_PREV(g), _PyGCHead_SET_PREV(g, p)
* _PyGCHead_FINALIZED(g), _PyGCHead_SET_FINALIZED(g)
* _PyGC_FINALIZED(o), _PyGC_SET_FINALIZED(o)
* _PyGC_PREV_MASK_FINALIZED
* _PyGC_PREV_MASK_COLLECTING
* _PyGC_PREV_SHIFT
* _PyGC_PREV_MASK
_PyObject_GC_TRACK(o) and _PyObject_GC_UNTRACK(o) remain in the
internal API.
#define _PyObject_GC_MAY_BE_TRACKED(obj) \
(PyObject_IS_GC(obj) && \
(!PyTuple_CheckExact(obj) || _PyObject_GC_IS_TRACKED(obj)))
-#endif
-
-#if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
/* Bit flags for _gc_prev */
/* Bit 0 is set when tp_finalize is called */
_PyGCHead_FINALIZED(_Py_AS_GC(o))
#define _PyGC_SET_FINALIZED(o) \
_PyGCHead_SET_FINALIZED(_Py_AS_GC(o))
+#endif /* !defined(Py_LIMITED_API) */
+
+#if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
/* Tell the GC to track this object.
*
* NB: While the object is tracked by the collector, it must be safe to call the