Exit the Emacs job and kill it.
If ARG is an integer, return ARG as the exit program code.
If ARG is a string, stuff it as keyboard input.
This function is called upon receipt of the signals SIGTERM
or SIGHUP, and upon SIGINT in batch mode.
The value of `kill-emacs-hook', if not void,
is a list of functions (of no args),
all of which are called before Emacs is actually killed. (fn &optional ARG)