This PR adds a cross-reference to the ellipsis object and the representation of recursive item in containers as indicated in [issue 9842](https://bugs.python.org/issue9842) by @bitdancer.


https://bugs.python.org/issue9842

This pull request adds some information about the special multipart/signed handling to clear about disabling header folding.


https://bugs.python.org/issue31887

Reported by ASAN.

Thanks!

Use `__GNUC__` instead of non-existing `__GNUC_MAJOR__`.





https://bugs.python.org/issue35147

Some methods in the os module can accept path-like objects. This is documented in the general documentation but not in the function docstrings. To keep both in sync, the docstrings need to be updated to reflect that path-like objects are also accepted.

Previous version was casting to Py_ssize_t incorrectly
and exhibited unexpected behavior on big-endian systems.

This could cause compile errors on macOS or other platforms.

https://bugs.python.org/issue35075

This implements getstate and setstate for the cjkcodecs multibyte incremental encoders/decoders, primarily to fix issues with seek/tell.

The encoder getstate/setstate is slightly tricky as the "state" is pending bytes + MultibyteCodec_State but only an integer can be returned. The approach I've taken is to encode this data into a long, similar to how .tell() encodes a "cookie_type" as a long.


https://bugs.python.org/issue33578

* And pycore_lifecycle.h and pycore_pathconfig.h headers to
  Include/internal/
* Move Py_BUILD_CORE specific code from coreconfig.h and
  pylifecycle.h to pycore_pathconfig.h and pycore_lifecycle.h
* Move _Py_wstrlist_XXX() definitions and _PyPathConfig code
  from pycore_state.h to pycore_pathconfig.h
* Move "Init" and "Fini" function definitions from pylifecycle.c to
  pycore_lifecycle.h.

The accu.h header is no longer part of the Python C API: it has been
moved to the "internal" headers which are restricted to Python
itself.

Replace #include "accu.h" with #include "pycore_accu.h".

If Py_BUILD_CORE is defined, the PyThreadState_GET() macro access
_PyRuntime which comes from the internal pycore_state.h header.
Public headers must not require internal headers.

Move PyThreadState_GET() and _PyInterpreterState_GET_UNSAFE() from
Include/pystate.h to Include/internal/pycore_state.h, and rename
PyThreadState_GET() to _PyThreadState_GET() there.

The PyThreadState_GET() macro of pystate.h is now redefined when
pycore_state.h is included, to use the fast _PyThreadState_GET().

Changes:

* Add _PyThreadState_GET() macro
* Replace "PyThreadState_GET()->interp" with
  _PyInterpreterState_GET_UNSAFE()
* Replace PyThreadState_GET() with _PyThreadState_GET() in internal C
  files (compiled with Py_BUILD_CORE defined), but keep
  PyThreadState_GET() in the public header files.
* _testcapimodule.c: replace PyThreadState_GET() with
  PyThreadState_Get(); the module is not compiled with Py_BUILD_CORE
  defined.
* pycore_state.h now requires Py_BUILD_CORE to be defined.

* Rename Include/internal/ header files:

  * pyatomic.h -> pycore_atomic.h
  * ceval.h -> pycore_ceval.h
  * condvar.h -> pycore_condvar.h
  * context.h -> pycore_context.h
  * pygetopt.h -> pycore_getopt.h
  * gil.h -> pycore_gil.h
  * hamt.h -> pycore_hamt.h
  * hash.h -> pycore_hash.h
  * mem.h -> pycore_mem.h
  * pystate.h -> pycore_state.h
  * warnings.h -> pycore_warnings.h

* PCbuild project, Makefile.pre.in, Modules/Setup: add the
  Include/internal/ directory to the search paths of header files.
* Update includes. For example, replace #include "internal/mem.h"
  with #include "pycore_mem.h".

Don't call _Py_FatalError_PrintExc() nor flush_std_files() if the
current thread doesn't hold the GIL, or if the current thread
has no Python state thread.

* Add #include "internal/mem.h" to C files using
  _PyMem_SetDefaultAllocator().
* Include/internal/mem.h now requires Py_BUILD_CORE to be defined.

_io.IncrementalNewlineDecoder's initializer possibly assigns out-of-range
value to the bitwise struct field.

The root widget was accessed as a global variable in the Application's method.

Add pyatomic.h to the VS project (it wasn't referenced).

* Remove _PyThreadState_Current
* Replace GET_TSTATE() with PyThreadState_GET()
* Replace GET_INTERP_STATE() with _PyInterpreterState_GET_UNSAFE()
* Replace direct access to _PyThreadState_Current with
  PyThreadState_GET()
* Replace _PyThreadState_Current with
  _PyRuntime.gilstate.tstate_current
* Rename SET_TSTATE() to _PyThreadState_SET(), name more
  consistent with _PyThreadState_GET()
* Update outdated comments

Convert _Py_Dealloc() macro into a static inline function. Moreover,
it is now also defined as a static inline function if Py_TRACE_REFS
is defined.

Make _PySys_AddXOptionWithError() and _PySys_AddWarnOptionWithError()
functions private again. They are no longer needed to initialize Python:
_PySys_EndInit() is now responsible to add these options instead.

Moreover, PySys_AddWarnOptionUnicode() now clears the exception on
failure if possible.

* bpo-34523, bpo-34403: Fix config_init_fs_encoding(): it now uses
  ASCII if _Py_GetForceASCII() is true.
* Fix a regression of commit b2457efc.
* Fix also a memory leak: get_locale_encoding() already allocates
  memory, no need to duplicate the string.

Use curses.ncurses_version for conditionally skipping a test.