* editfns.c: Integer and memory overflow fixes.

* editfns.c: Integer and memory overflow fixes.

(set_time_zone_rule): Don't assume environment length fits in int.
(message_length): Now ptrdiff_t, not int.
(Fmessage_box): Don't update size until allocation succeeds.
Don't assume message length fits in int.
(Fformat): Use ptrdiff_t, not EMACS_INT, where ptrdiff_t will do.