* linux-low.c (linux_attach_lwp): Do not _exit after errors.

	* linux-low.c (linux_attach_lwp): Do not _exit after errors.
	(linux_kill, linux_detach): Clean up the process list.
	* remote-utils.c (remote_open): Improve port number parsing.
	(putpkt_binary, input_interrupt): Only send interrupts if the target
	is running.
	* server.c (extended_protocol): Make static.
	(attached): Define earlier.
	(exit_requested, response_needed, program_argv): New variables.
	(target_running): New.
	(start_inferior): Clear attached here.
	(attach_inferior): Set attached here.
	(require_running): Define.
	(handle_query): Use require_running and target_running.  Implement
	"monitor exit".
	(handle_v_attach, handle_v_run): New.
	(handle_v_requests): Use require_running.  Handle vAttach and vRun.
	(gdbserver_usage): Update.
	(main): Redo argument parsing.  Handle --debug and --multi.  Handle
	--attach along with other options or after the port.  Save
	program_argv.  Support no initial program.  Resynchronize
	communication with GDB after an error.  Handle "monitor exit".
	Use require_running and target_running.  Always allow the extended
	protocol.  Do not error out for Hc0 or Hc-1.  Do not automatically
	restart in extended mode.
	* README: Refer to the GDB manual.  Update --attach usage.

	* remote.c (struct remote_state): Add cached_wait_status.
	(remote_exec_file): New variable.
	(PACKET_vAttach, PACKET_vRun): New constants.
	(extended_remote_restart): Do not query for status.
	(struct start_remote_args): New.
	(remote_start_remote): Take it as a second argument.  Check
	whether the target is running.  Issue an error for non-running
	non-extended targets.  Cache the wait status.  Set inferior_ptid
	here.
	(remote_open_1): Prompt to disconnect non-running targets.  Make
	sure the target is marked running.  Do not set inferior_ptid here.
	Update call to remote_start_remote.  Do not call remote_check_symbols
	if the target is not running.
	(remote_detach_1): Rename from remote_detach.  Take an EXTENDED
	argument.  Handle a non-running target.
	(remote_detach): Use it.
	(extended_remote_detach): New.
	(remote_disconnect): Fix typo.  Use remoute_mourn_1.
	(extended_remote_attach_1, extended_remote_attach)
	(extended_async_remote_attach): New.
	(remote_vcont_resume): Remove unused variable.
	(remote_wait, remote_async_wait): Use any cached wait status.
	(putpkt_binary, getpkt): Clear any cached wait status.
	(extended_remoute_mourn_1): New.
	(extended_remote_mourn): Use it.
	(extended_async_remote_mourn, extended_remote_run): New.
	(extended_remote_create_inferior_1): New.
	(extended_remote_create_inferior): Use it.
	(extended_remote_async_create_inferior): Likewise.
	(remote_xfer_partial): Skip for non-executing targets.
	(init_extended_remote_ops): Set to_detach and to_attach.
	(init_extended_async_remote_ops): Likewise.  Use
	extended_async_remote_mourn.
	(_initialize_remote): Register vAttach, vRun, and
	set remote exec-file.
	* NEWS: Mention vAttach, vRun, and gdbserver extended-remote support.

	* gdb.server/ext-attach.c, gdb.server/ext-attach.exp,
	gdb.server/ext-run.exp: New files.
	* lib/gdbserver-support.exp (gdbserver_download): New.
	(gdbserver_start): New.  Update gdbserver expected
	output.
	(gdbserver_spawn): Use them.
	(gdbserver_start_extended): New.

	* gdb.texinfo (Using the `gdbserver' Program): Add security
	warning.  Rearrange into subsections and subsubsections.  Document
	--multi and --debug.  Correct --with-sysroot typo.  Update --attach
	usage.  Make load reference clearer.  Document monitor exit.
	(Remote Configuration): Document set remote exec-file, attach-packet,
	and run-packet.
	(Packets): Document vAttach and vRun.