Replace old names when they refer to actual versions of macOS.
Keep historical names in references to older versions.

Co-authored-by: Patrick Reader <_@pxeger.com>
(cherry picked from commit 36122e18148c5b6c78ebce1d36d514fd7cf250f5)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Removed stray semicolon which was causing the docs to render weirdly (it's the function right under the one [here](https://docs.python.org/3/c-api/init.html#c._PyInterpreterState_GetEvalFrameFunc)).

Fix _PyConfig_Read() if compute_path_config=0: use values set by
Py_SetPath(), Py_SetPythonHome() and Py_SetProgramName(). Add
compute_path_config parameter to _PyConfig_InitPathConfig().

The following functions now return NULL if called before
Py_Initialize():

* Py_GetExecPrefix()
* Py_GetPath()
* Py_GetPrefix()
* Py_GetProgramFullPath()
* Py_GetProgramName()
* Py_GetPythonHome()

These functions no longer automatically computes the Python Path
Configuration. Moreover, Py_SetPath() no longer computes
program_full_path.

Add "borrowed reference" and "strong reference" to the documentation
glossary.

Enhance also Py_INCREF() and Py_NewRef() documentation.

Enhance the documentation of the Python startup, filesystem encoding
and error handling, locale encoding. Add a new "Python UTF-8 Mode"
section.

* Add "locale encoding" and "filesystem encoding and error handler"
  to the glossary
* Remove documentation from Include/cpython/initconfig.h: move it to
  Doc/c-api/init_config.rst.
* Doc/c-api/init_config.rst:

  * Document command line options and environment variables
  * Document default values.

* Add a new "Python UTF-8 Mode" section in Doc/library/os.rst.
* Add warnings to Py_DecodeLocale() and Py_EncodeLocale() docs.
* Document how Python selects the filesystem encoding and error
  handler at a single place: PyConfig.filesystem_encoding and
  PyConfig.filesystem_errors.
* PyConfig: move orig_argv member at the right place.

For example, fix the following Sphinx 3 errors:

Doc/c-api/buffer.rst:102: WARNING: Error in declarator or parameters
Invalid C declaration: Expected identifier in nested name. [error at 5]
  void \*obj
  -----^

Doc/c-api/arg.rst:130: WARNING: Unparseable C cross-reference: 'PyObject*'
Invalid C declaration: Expected end of definition. [error at 8]
  PyObject*
  --------^

The modified documentation is compatible with Sphinx 2 and Sphinx 3.

The PyThreadState_GetFrame() function now returns a strong reference
to the frame.

PyFrame_GetCode(frame): return a borrowed reference to the frame
code.

Replace frame->f_code with PyFrame_GetCode(frame) in most code,
except in frameobject.c, genobject.c and ceval.c.

Also add PyFrame_GetLineNumber() to the limited C API.

* Replace PY_INT64_T with int64_t
* Replace PY_UINT32_T with uint32_t
* Replace PY_UINT64_T with uint64_t

sha3module.c no longer checks if PY_UINT64_T is defined since it's
always defined and uint64_t is always available on platforms
supported by Python.

Fix PyInterpreterState_New(): Don't call PyErr_SetString() when there
is no current Python thread state (if tstate is NULL).