This changeset does two things: introduces a new RemoteDisconnected exception
(that subclasses ConnectionResetError and BadStatusLine) so that a remote
server disconnection can be detected by client code (and provides a better
error message for debugging purposes), and ensures that the client socket is
closed if a ConnectionError happens, so that the automatic re-connection code
can work if the application handles the error and continues on.

Tests are added that confirm that a connection is re-used or not re-used
as appropriate to the various combinations of protocol version and headers.

Patch by Martin Panter, reviewed by Demian Brecht.  (Tweaked only slightly by
me.)

array_array_frombytes() is used in other functions, but it's signature was
changed. Closes issue #23866.

returns bool.  tkinter.BooleanVar now validates input values (accepted bool,
int, str, and Tcl_Obj).  tkinter.BooleanVar.get() now always returns bool.

returns bool.  tkinter.BooleanVar now validates input values (accepted bool,
int, str, and Tcl_Obj).  tkinter.BooleanVar.get() now always returns bool.

Patch by Makoto Kato.

Patch by Makoto Kato.

PyArg_Parse instead of PyArg_ParseTuple if possible.

(empty) definition of the methoddef macro: it's only generated once, even
if Argument Clinic processes the same symbol multiple times, and it's emitted
at the end of all processing rather than immediately after the first use.

the wait is cancelled, the future *fut* is now also cancelled.

in Parser/pgen.c.

@unittest.skipUnless(ssl, '...') doesn't work because the class body uses the
nntplib.NNTP_SSL attribute which doesn't exist.

* Rename check_socket_and_wait_for_timeout() to PySSL_select()
* PySSL_select() is now clearly splitted betwen poll() and select()
* Add empty lines for readability

* Use the new _PyTime_FromSeconds() function to set the timeout to -1 second
  for socket.settimeout(None). It avoids a special case in internal_select()
  because of a rounding issue: -1 nanosecond is rounded to 0 millisecond which
  means non-blocking, instead of blocking.
* Check if the interval the negative in sock_call_ex() instead of doing the
  check in internal_select(). sock_call_ex() remembers if the socket has a
  timeout or not, which avoids a race condition if the timeout is modified in a
  different thread.