* composite.c: Use int, not EMACS_INT, for characters.

* composite.c: Use int, not EMACS_INT, for characters.

(fill_gstring_body, composition_compute_stop_pos): Use int, not
EMACS_INT, for values that are known to be in character range.
This doesn't fix any bugs but is the usual style inside Emacs and
may generate better code on 32-bit machines.