Per-inferior args and tty and environment.

	Per-inferior args and tty and environment.

	* infcmd.c (inferior_args): Rename to ...
	(inferior_args_scratch): ... this.
	(inferior_io_terminal): Rename to ...
	(inferior_io_terminal_scratch): ... this.
	(inferior_argc, inferior_argv): Remove.
	(set_inferior_io_terminal, get_inferior_io_terminal): Store
	inside current_inferior().
	(set_inferior_tty_command, show_inferior_tty_command): New.
	(get_inferior_args, set_inferior_args): Store inside
	current_inferior().
	(notice_args_set): Likewise and rename to...
	(set_args_command): ... this.
	(set_inferior_args_vector): Likewise.
	(notice_args_read): Rename to...
	(show_args_command): ...new.
	(tty_command): Remove.
	(run_command_1): Don't free old args, as they are freed by
	set_inferior_arg now.
	(run_no_args_command): Likewise.
	(inferior_environ): Remove.
	(run_command_1): Use environment of the current inferior.
	(environment_info, set_environment_command)
	(unset_environment_command, path_info, path_command): Likewise.
	(_initialize_infcmd): Adjust for function and variable renames.
	Do not init inferior_environ.
	* inferior.h (set_inferior_arg): Adjust prototype.
	(struct inferior): New fields args, argc, argv, terminal, environment.
	(inferior_environ): Remove declaration.
	* inferior.c (free_inferior): Free new fields.
	(add_inferior_silent): Initialize 'environment' field.
	* main.c (captured_main): Set arguments only after the initial
	inferior has been created.  Set set_inferior_io_terminal,
	not tty_command.
	* mi/mi-main.c (mi_cmd_env_path): Use environment of the current
	inferior.
	(_initialize_mi_cmd_env): Adjust for disappearance of global
	inferior_environ.
	* solib.c (solib_find): Use environment of the current inferior.