Run kill-emacs when exiting for display closed or SIGTERM/HUP.

Run kill-emacs when exiting for display closed or SIGTERM/HUP.

* xsmfns.c (CHDIR_OPT): New define.
(smc_save_yourself_CB): Add CHDIR_OPT to options to use when
restarting emacs.

* xterm.c (x_connection_closed): Call Fkill_emacs instead of
shut_down_emacs.

* emacs.c (USAGE1): Mention --chdir.
(main): Handle --chdir.
(standard_args): Add --chdir.
(fatal_error_signal): Call Fkill_emacs for SIGTERM and SIGHUP (Bug
#5552).

* cmdargs.texi (Initial Options): Mention --chdir.