Use bool for boolean in xfns.c

Use bool for boolean in xfns.c

* xfaces.c (x_update_menu_appearance):
* xfns.c (x_real_positions, x_defined_color, x_decode_color)
(xg_set_icon, xg_set_icon_from_xpm_data, x_set_cursor_color)
(x_set_icon_type, x_set_icon_name, x_set_menu_bar_lines)
(x_change_tool_bar_height, x_set_internal_border_width)
(x_encode_text, x_set_name_internal, x_explicitly_set_name)
(x_implicitly_set_name, x_default_scroll_bar_color_parameter)
(hack_wm_protocols, xic_create_fontsetname, xic_free_xfontset)
(x_window, x_icon, Fx_wm_set_size_hint, Fx_create_frame)
(Fxw_color_defined_p, Fxw_color_values, x_create_tip_frame)
(Fx_show_tip, clean_up_file_dialog, Fx_file_dialog)
(clean_up_dialog, syms_of_xfns):
* xterm.h (xg_set_icon, xg_set_icon_from_xpm_data)
(xic_create_fontsetname):
Use bool for boolean.
* xfns.c: Include bitmaps/gray.xbm unconditionally.