Multiexec MI

	Multiexec MI

	* breakpoint.c (clear_syscall_counts): Take struct inferior*.
	* inferior.c (add_inferior_silent): Notify inferior_added
	observer.
	(delete_inferior_1): Notify inferior_removed observer.
	(exit_inferior_1): Pass inferior, not pid, to observer.
	(inferior_appeared): Likewise.
	(add_inferior_with_spaces): New.
	(add_inferior_command): Use the above.
	* inferior.h (delete_inferior_1, add_inferior_with_spaces):
	Declare.

	* inflow.c (inflow_inferior_exit): Likewise.
	* jit.c (jit_inferior_exit_hook): Likewise.

	* mi/mi-cmds.c (mi_cmds): Register add-inferior and
	remove-inferior.
	* mi/mi-cmds.h (mi_cmd_add_inferior, mi_cmd_remove_inferior): New.
	* mi/mi-interp.c (mi_inferior_added, mi_inferior_removed): New.
	(report_initial_inferior): New.
	(mi_inferior_removed): Register the above. Make sure
	inferior_added observer is called on the first inferior.
	(mi_new_thread, mi_thread_exit): Thread group is now identified by
	inferior number, not pid.
	(mi_solib_loaded, mi_solib_unloaded): Report which inferiors are
	affected.
	* mi/mi-main.c (current_context): New.
	(proceed_thread_callback): Use typed closure.
	Proceed everything if pid is 0. Most implementation split into
	(proceed_thread): ... this.
	(run_one_inferior): New.
	(mi_cmd_exec_continue, mi_cmd_exec_interrupt, mi_cmd_exec_run):
	Adjust for multiexec behaviour.
	(mi_cmd_add_inferior, mi_cmd_remove_inferior): New.
	(mi_cmd_execute): Handle the 'thread-group' option here.
	Do some extra checks.
	* mi-parse.c (mi_parse): Handle the --all and --thread-group
	options.
	* mi-parse.h (struct mi_parse): New fields all and thread_group.