* window.h (WINDOW_FRINGE_EXTENDED_P): New macro.

* window.h (WINDOW_FRINGE_EXTENDED_P): New macro.
* nsterm.m (ns_set_vertical_scroll_bar): Use it.  Use convenient
bool instead of BOOL.
* w32term.h (struct scroll_bar): Convert fringe_extended_p
from Lisp_Object to bitfield.  Adjust comment.
* w32term.c (x_scroll_bar_create): Adjust user.
Use WINDOW_FRINGE_EXTENDED_P and bool for boolean.
* xterm.c (XTset_vertical_scroll_bar): Likewise.
Use bool for boolean.
* xterm.h (struct scroll_bar): Prefer commonly used `unsigned'
to `unsigned int' when defining a bitfield.