* keyboard.c: Overflow, signedness and related fixes.

* keyboard.c: Overflow, signedness and related fixes.

(make_lispy_movement): Use same integer type in forward decl
that is used in the definition.
(read_key_sequence, keyremap_step):
Change bufsize argument back to int, undoing my 2011-03-30 change.
We prefer signed types, and int is wide enough here.
(parse_tool_bar_item): Don't assume tool_bar_max_label_size is less
than TYPE_MAXIMUM (EMACS_INT) / 2.  Don't let the label size grow
larger than STRING_BYTES_BOUND.  Use ptrdiff_t for Emacs string
length, not size_t.  Use ptrdiff_t for index, not int.
(keyremap_step, read_key_sequence): Redo bufsize check to avoid
possibility of integer overflow.