Move private _PyMem functions to the internal C API (pycore_pymem.h):
* _PyMem_GetCurrentAllocatorName()
* _PyMem_RawStrdup()
* _PyMem_RawWcsdup()
* _PyMem_Strdup()
No longer export these functions.
Move pymem_getallocatorsname() function from _testcapi to _testinternalcapi,
since the API moved to the internal C API.
Move private debug _PyObject functions to the internal C API
(pycore_object.h):
* _PyDebugAllocatorStats()
* _PyObject_CheckConsistency()
* _PyObject_DebugTypeStats()
* _PyObject_IsFreed()
No longer export most of these functions, except of
_PyObject_IsFreed().
Move test functions using _PyObject_IsFreed() from _testcapi to
_testinternalcapi. check_pyobject_is_freed() test no longer catch
_testcapi.error: the tested function cannot raise _testcapi.error.
* Remove private _PyTraceMalloc C API functions: move them to the
internal C API.
* Don't export most of these functions anymore, but still export
_PyTraceMalloc_GetTraceback() used by tests.
* Rename Include/tracemalloc.h to Include/cpython/tracemalloc.h
* Eliminate all remaining uses of Py_SIZE and Py_SET_SIZE on PyLongObject, adding asserts.
* Change layout of size/sign bits in longobject to support future addition of immortal ints and tagged medium ints.
* Add functions to hide some internals of long object, and for setting sign and digit count.
* Replace uses of IS_MEDIUM_VALUE macro with _PyLong_IsCompact().
