* character.c (lisp_string_width): Check for string overflow.

* character.c (lisp_string_width): Check for string overflow.

Use EMACS_INT, not int, for string indexes and lengths; in
particular, 2nd arg is now EMACS_INT, not int.  Do not crash if
the resulting string length overflows an EMACS_INT; instead,
report a string overflow if no precision given.  When checking for
precision exhaustion, use a check that cannot possibly have
integer overflow.  (Bug#8675)
* character.h (lisp_string_width): Adjust to new signature.