This commit is the result of running the gdb/copyright.py script,
which automated the update of the copyright year range for all
source files managed by the GDB project to be updated to include
year 2023.

Currently, Python code can use event registries to detect when gdb
loads a new objfile, and when gdb clears the objfile list.  However,
there's no way to detect the removal of an objfile, say when the
inferior calls dlclose.

This patch adds a gdb.free_objfile event registry and arranges for an
event to be emitted in this case.

This commit brings all the changes made by running gdb/copyright.py
as per GDB's Start of New Year Procedure.

For the avoidance of doubt, all changes in this commits were
performed by the script.

This commit adds a new object type gdb.TargetConnection.  This new
type represents a connection within GDB (a connection as displayed by
'info connections').

There's three ways to find a gdb.TargetConnection, there's a new
'gdb.connections()' function, which returns a list of all currently
active connections.

Or you can read the new 'connection' property on the gdb.Inferior
object type, this contains the connection for that inferior (or None
if the inferior has no connection, for example, it is exited).

Finally, there's a new gdb.events.connection_removed event registry,
this emits a new gdb.ConnectionEvent whenever a connection is removed
from GDB (this can happen when all inferiors using a connection exit,
though this is not always the case, depending on the connection type).
The gdb.ConnectionEvent has a 'connection' property, which is the
gdb.TargetConnection being removed from GDB.

The gdb.TargetConnection has an 'is_valid()' method.  A connection
object becomes invalid when the underlying connection is removed from
GDB (as discussed above, this might be when all inferiors using a
connection exit, or it might be when the user explicitly replaces a
connection in GDB by issuing another 'target' command).

The gdb.TargetConnection has the following read-only properties:

  'num': The number for this connection,

  'type': e.g. 'native', 'remote', 'sim', etc

  'description': The longer description as seen in the 'info
                 connections' command output.

  'details': A string or None.  Extra details for the connection, for
             example, a remote connection's details might be
             'hostname:port'.

Add a new event, gdb.events.gdb_exiting, which is called once GDB
decides it is going to exit.

This event is not triggered in the case that GDB performs a hard
abort, for example, when handling an internal error and the user
decides to quit the debug session, or if GDB hits an unexpected,
fatal, signal.

This event is triggered if the user just types 'quit' at the command
prompt, or if GDB is run with '-batch' and has processed all of the
required commands.

The new event type is gdb.GdbExitingEvent, and it has a single
attribute exit_code, which is the value that GDB is about to exit
with.

The event is triggered before GDB starts dismantling any of its own
internal state, so, my expectation is that most Python calls should
work just fine at this point.

When considering this functionality I wondered about using the
'atexit' Python module.  However, this is triggered when the Python
environment is shut down, which is done from a final cleanup.  At
this point we don't know for sure what other GDB state has already
been cleaned up.

This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...

gdb/ChangeLog

        Update copyright year range in copyright header of all GDB files.

gdb/ChangeLog:

        Update copyright year range in all GDB files.

This commit applies all changes made after running the gdb/copyright.py
script.

Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.

gdb/ChangeLog:

	Update copyright year range in all GDB files.

gdb/ChangeLog:

        Update copyright year range in all GDB files

The first patch in this series went through several iterations as I'd
forgotten how many places had to be touched to add a new event and a
new event type.

This patch simplifies the process using two new ".def" files.  Now, a
new event type can be added by adding a line to "py-event-types.def",
and a new event registry can be added by adding a line to
"py-all-events.def".

ChangeLog
2017-09-11  Tom Tromey  <tom@tromey.com>

	* python/python.c (do_start_initialization): Use
	py-event-types.def to initialize types.
	Define all object type structures.
	* python/python-internal.h: Don't declare event initialization
	functions.
	* python/py-threadevent.c (thread_event_object_type): Don't
	define.
	* python/py-stopevent.c (stop_event_object_type): Don't define.
	* python/py-signalevent.c (signal_event_object_type): Don't
	declare or define.
	* python/py-newobjfileevent.c (new_objfile_event_object_type)
	(clear_objfiles_event_object_type): Don't declare or define.
	* python/py-infevents.c (inferior_call_pre_event_object_type)
	(inferior_call_post_event_object_type)
	(register_changed_event_object_type)
	(memory_changed_event_object_type): Don't declare or define.
	* python/py-inferior.c (new_thread_event_object_type)
	(new_inferior_event_object_type)
	(inferior_deleted_event_object_type): Don't declare or define.
	* python/py-exitedevent.c (exited_event_object_type): Don't
	declare or define.
	* python/py-evts.c (gdbpy_initialize_py_events): Use
	py-all-events.def.
	* python/py-events.h (thread_event_object_type): Don't declare.
	(events_object): Use py-all-events.def.
	* python/py-event.h (GDBPY_NEW_EVENT_TYPE): Remove.  Use
	py-event-types.def.
	* python/py-event-types.def: New file.
	* python/py-continueevent.c (create_continue_event_object): Don't
	declare or define.
	* python/py-bpevent.c (breakpoint_event_object_type): Don't
	declare or define.
	* python/py-all-events.def: New file.