(window_scroll_line_based, Frecenter):
Check that an Emacs fixnum is in range before assigning it to 'int'.
(Frecenter, Fmove_to_window_line): Use EMACS_INT, not int, for
values converted from Emacs fixnums.
(Frecenter): Don't wrap around a line count if it is out of 'int'
range; instead, treat it as an extreme value.
(Fset_window_configuration, compare_window_configurations):
Use ptrdiff_t, not int, for index that might exceed 2 GiB.