Make it simpler to add events to Python

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.

gdb/python/py-event-types.def

@@ -0,0 +1,107 @@
+/* Python event definitions -*- c++ -*-
+
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* To use this file, define GDB_PY_DEFINE_EVENT_TYPE to expand how you
+   like, then include the file.
+
+   Each invocation is of the form:
+
+   GDB_PY_DEFINE_EVENT_TYPE(name, py_name, doc, base)
+
+   NAME is the name of the event.
+   PY_NAME a string representing what the event should be called in
+   python.
+   DOC Python documentation for the new event type
+   BASE the base event for this event usually just event_object_type.
+*/
+
+GDB_PY_DEFINE_EVENT_TYPE (breakpoint,
+			  "BreakpointEvent",
+			  "GDB breakpoint stop event object",
+			  stop_event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (continue,
+			  "ContinueEvent",
+			  "GDB continue event object",
+			  thread_event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (exited,
+			  "ExitedEvent",
+			  "GDB exited event object",
+			  event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (new_thread,
+			  "NewThreadEvent",
+			  "GDB new thread event object",
+			  thread_event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (new_inferior,
+			  "NewInferiorEvent",
+			  "GDB new inferior event object",
+			  event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (inferior_deleted,
+			  "InferiorDeletedEvent",
+			  "GDB inferior deleted event object",
+			  event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (inferior_call_pre,
+			  "InferiorCallPreEvent",
+			  "GDB inferior function pre-call event object",
+			  event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (inferior_call_post,
+			  "InferiorCallPostEvent",
+			  "GDB inferior function post-call event object",
+			  event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (register_changed,
+			  "RegisterChangedEvent",
+			  "GDB register change event object",
+			  event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (memory_changed,
+			  "MemoryChangedEvent",
+			  "GDB memory change event object",
+			  event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (new_objfile,
+			  "NewObjFileEvent",
+			  "GDB new object file event object",
+			  event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (clear_objfiles,
+			  "ClearObjFilesEvent",
+			  "GDB clear object files event object",
+			  event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (signal,
+			  "SignalEvent",
+			  "GDB signal event object",
+			  stop_event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (stop,
+			  "StopEvent",
+			  "GDB stop event object",
+			  thread_event_object_type);
+
+GDB_PY_DEFINE_EVENT_TYPE (thread,
+			  "ThreadEvent",
+			  "GDB thread event object",
+			  event_object_type);