GDBserver disconnected tracing support.

* linux-low.c (linux_remove_process): Delete.
	(add_lwp): Don't set last_resume_kind here.
	(linux_kill): Use `mourn'.
	(linux_detach): Use `thread_db_detach', and `mourn'.
	(linux_mourn): New.
	(linux_attach_lwp_1): Adjust comment.
	(linux_attach): last_resume_kind moved the thread_info; adjust.
	(status_pending_p_callback): Adjust.
	(linux_wait_for_event_1): Adjust.
	(count_events_callback, select_singlestep_lwp_callback)
	(select_event_lwp_callback, cancel_breakpoints_callback)
	(db_wants_lwp_stopped, linux_wait_1, need_step_over_p)
	(proceed_one_lwp): Adjust.
	(linux_async): Add debug output.
	(linux_thread_stopped): New.
	(linux_pause_all): New.
	(linux_target_ops): Install linux_mourn, linux_thread_stopped and
	linux_pause_all.
	* linux-low.h (struct lwp_info): Delete last_resume_kind field.
	(thread_db_free): Delete declaration.
	(thread_db_detach, thread_db_mourn): Declare.
	* thread-db.c (thread_db_init): Use thread_db_mourn.
	(thread_db_free): Delete, split in two.
	(disable_thread_event_reporting): New.
	(thread_db_detach): New.
	(thread_db_mourn): New.

	* server.h (struct thread_info) <last_resume_kind>: New field.
	<attached>: Add comment.
	<gdb_detached>: New field.
	(handler_func): Change return type to int.
	(handle_serial_event, handle_target_event): Ditto.
	(gdb_connected): Declare.
	(tracing): Delete.
	(disconnected_tracing): Declare.
	(stop_tracing): Declare.

	* server.c (handle_query) <qSupported>: Report support for
	disconnected tracing.
	(queue_stop_reply_callback): Account for running threads.
	(gdb_wants_thread_stopped): New.
	(gdb_wants_all_threads_stopped): New.
	(gdb_reattached_process): New.
	(handle_status): Clear the `gdb_detached' flag of all processes.
	In all-stop, stop all threads.
	(main): Be sure to leave tfind mode.  Handle disconnected tracing.
	(process_serial_event): If the remote connection breaks, or if an
	exit was forced with "monitor exit", force an event loop exit.
	Handle disconnected tracing on detach.
	(handle_serial_event): Adjust.
	(handle_target_event): If GDB isn't connected, forward events back
	to the inferior, unless the last process exited, in which case,
	exit gdbserver.  Adjust interface.

	* remote-utils.c (remote_open): Don't block in accept.  Instead
	register an event loop source on the listen socket file
	descriptor.  Refactor bits into ...
	(listen_desc): ... this new global.
	(gdb_connected): ... this new function.
	(enable_async_notification): ... this new function.
	(handle_accept_event): ... this new function.
	(remote_close): Clear remote_desc.

	* inferiors.c (add_thread): Set the new thread's last_resume_kind.

	* target.h (struct target_ops) <mourn, thread_stopped, pause_all>:
	New fields.
	(mourn_inferior): Define.
	(target_process_qsupported): Avoid the dangling else problem.
	(thread_stopped): Define.
	(pause_all): Define.
	(target_waitstatus_to_string): Declare.
	* target.c (target_waitstatus_to_string): New.

	* tracepoint.c (tracing): Make extern.
	(disconnected_tracing): New.
	(stop_tracing): Make extern.  Handle tracing stops due to GDB
	disconnecting.
	(cmd_qtdisconnected): New.
	(cmd_qtstatus): Report disconnected tracing status in trace reply.
	(handle_tracepoint_general_set): Handle QTDisconnected.

	* event-loop.c (event_handler_func): Change return type to int.
	(process_event): Bail out if the event handler wants the event
	loop to stop.
	(handle_file_event): Ditto.
	(start_event_loop): Bail out if the event handler wants the event
	loop to stop.

	* nto-low.c (nto_target_ops): Adjust.
	* spu-low.c (spu_wait): Don't remove the process here.
	(spu_target_ops): Adjust.
	* win32-low.c (win32_wait): Don't remove the process here.
	(win32_target_ops): Adjust.

gdb/gdbserver/target.h

@@ -138,6 +138,10 @@ struct target_ops
 
   int (*detach) (int pid);
 
+  /* The inferior process has died.  Do what is right.  */
+
+  void (*mourn) (struct process_info *proc);
+
   /* Wait for inferior PID to exit.  */
   void (*join) (int pid);
 
@@ -299,6 +303,12 @@ struct target_ops
 
   /* Write PC to REGCACHE.  */
   void (*write_pc) (struct regcache *regcache, CORE_ADDR pc);
+
+  /* Return true if THREAD is known to be stopped now.  */
+  int (*thread_stopped) (struct thread_info *thread);
+
+  /* Pause all threads.  */
+  void (*pause_all) (void);
 };
 
 extern struct target_ops *the_target;
@@ -317,6 +327,9 @@ void set_target_ops (struct target_ops *);
 #define detach_inferior(pid) \
   (*the_target->detach) (pid)
 
+#define mourn_inferior(PROC) \
+  (*the_target->mourn) (PROC)
+
 #define mythread_alive(pid) \
   (*the_target->thread_alive) (pid)
 
@@ -339,14 +352,27 @@ void set_target_ops (struct target_ops *);
   (the_target->supports_multi_process ? \
    (*the_target->supports_multi_process) () : 0)
 
-#define target_process_qsupported(query) \
-  if (the_target->process_qsupported) \
-    the_target->process_qsupported (query)
+#define target_process_qsupported(query)		\
+  do							\
+    {							\
+      if (the_target->process_qsupported)		\
+	the_target->process_qsupported (query);		\
+    } while (0)
 
 #define target_supports_tracepoints()			\
   (the_target->supports_tracepoints			\
    ? (*the_target->supports_tracepoints) () : 0)
 
+#define thread_stopped(thread) \
+  (*the_target->thread_stopped) (thread)
+
+#define pause_all()			\
+  do					\
+    {					\
+      if (the_target->pause_all)	\
+	(*the_target->pause_all) ();	\
+    } while (0)
+
 /* Start non-stop mode, returns 0 on success, -1 on failure.   */
 
 int start_non_stop (int nonstop);
@@ -363,4 +389,6 @@ void set_desired_inferior (int id);
 
 const char *target_pid_to_str (ptid_t);
 
+const char *target_waitstatus_to_string (const struct target_waitstatus *);
+
 #endif /* TARGET_H */