gh-79315: Add Include/cpython/sliceobject.h header (#139729)

Include/sliceobject.h

@@ -16,19 +16,6 @@ PyAPI_DATA(PyObject) _Py_EllipsisObject; /* Don't use this directly */
 
 /* Slice object interface */
 
-/*
-
-A slice object containing start, stop, and step data members (the
-names are from range).  After much talk with Guido, it was decided to
-let these be any arbitrary python type.  Py_None stands for omitted values.
-*/
-#ifndef Py_LIMITED_API
-typedef struct {
-    PyObject_HEAD
-    PyObject *start, *stop, *step;      /* not NULL */
-} PySliceObject;
-#endif
-
 PyAPI_DATA(PyTypeObject) PySlice_Type;
 PyAPI_DATA(PyTypeObject) PyEllipsis_Type;
 
@@ -36,12 +23,6 @@ PyAPI_DATA(PyTypeObject) PyEllipsis_Type;
 
 PyAPI_FUNC(PyObject *) PySlice_New(PyObject* start, PyObject* stop,
                                   PyObject* step);
-#ifndef Py_LIMITED_API
-PyAPI_FUNC(PyObject *) _PySlice_FromIndices(Py_ssize_t start, Py_ssize_t stop);
-PyAPI_FUNC(int) _PySlice_GetLongIndices(PySliceObject *self, PyObject *length,
-                                 PyObject **start_ptr, PyObject **stop_ptr,
-                                 PyObject **step_ptr);
-#endif
 PyAPI_FUNC(int) PySlice_GetIndices(PyObject *r, Py_ssize_t length,
                                   Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step);
 Py_DEPRECATED(3.7)
@@ -63,6 +44,12 @@ PyAPI_FUNC(Py_ssize_t) PySlice_AdjustIndices(Py_ssize_t length,
                                              Py_ssize_t step);
 #endif
 
+#ifndef Py_LIMITED_API
+#  define Py_CPYTHON_SLICEOBJECT_H
+#  include "cpython/sliceobject.h"
+#  undef Py_CPYTHON_SLICEOBJECT_H
+#endif
+
 #ifdef __cplusplus
 }
 #endif