Py_REFCNT(), Py_TYPE(), Py_SIZE() and Py_IS_TYPE() functions argument
type is now "PyObject*", rather than "const PyObject*".
* Replace also "const PyObject*" with "PyObject*" in functions:
* _Py_strhex_impl()
* _Py_strhex_with_sep()
* _Py_strhex_bytes_with_sep()
* Remove _PyObject_CAST_CONST() and _PyVarObject_CAST_CONST() macros.
* Py_IS_TYPE() can now use Py_TYPE() in its implementation.
Move Include/pystrhex.h to Include/internal/pycore_strhex.h.
The header file only contains private functions.
The following C extensions are now built with Py_BUILD_CORE_MODULE
macro defined to get access to the internal C API:
* _blake2
* _hashopenssl
* _md5
* _sha1
* _sha3
* _ssl
* binascii