* Rename PyThreadState_DeleteCurrent()
  to _PyThreadState_DeleteCurrent()
* Move it to the internal C API

Co-Authored-By: Carol Willing <carolcode@willingconsulting.com>

Only AttributeError should be silenced.

In a subinterpreter, spawning a daemon thread now raises an
exception. Daemon threads were never supported in subinterpreters.
Previously, the subinterpreter finalization crashed with a Pyton
fatal error if a daemon thread was still running.

* Add _thread._is_main_interpreter()
* threading.Thread.start() now raises RuntimeError if the thread is a
  daemon thread and the method is called from a subinterpreter.
* The _thread module now uses Argument Clinic for the new function.
* Use textwrap.dedent() in test_threading.SubinterpThreadingTests

This reverts commit 396e0a8d9dc65453cb9d53500d0a620602656cfe.

https://bugs.python.org/issue36818

Automatically replace
tp_print -> tp_vectorcall_offset
tp_compare -> tp_as_async
tp_reserved -> tp_as_async

_thread.start_new_thread() now logs uncaught exception raised by the
function using sys.unraisablehook(), rather than sys.excepthook(), so
the hook gets access to the function which raised the exception.

Add a new threading.excepthook() function which handles uncaught
Thread.run() exception. It can be overridden to control how uncaught
exceptions are handled.

threading.ExceptHookArgs is not documented on purpose: it should not
be used directly.

* threading.excepthook() and threading.ExceptHookArgs.
* Add _PyErr_Display(): similar to PyErr_Display(), but accept a
  'file' parameter.
* Add _thread._excepthook(): C implementation of the exception hook
  calling _PyErr_Display().
* Add _thread._ExceptHookArgs: structseq type.
* Add threading._invoke_excepthook_wrapper() which handles the gory
  details to ensure that everything remains alive during Python
  shutdown.
* Add unit tests.

Add native thread ID (TID) to threading.Thread objects
(supported platforms: Windows, FreeBSD, Linux, macOS).