Use bool for boolean in w32fns.c

Use bool for boolean in w32fns.c

 src/w32fns.c (w32_defined_color, x_decode_color)
 (Fxw_color_defined_p, Fxw_color_values, x_set_icon_type)
 (x_set_menu_bar_lines, x_change_tool_bar_height)
 (x_set_internal_border_width, x_explicitly_set_name)
 (x_implicitly_set_name, Fx_create_frame, w32_window)
 (x_create_tip_frame, Fx_show_tip): Use bool where appropriate.