* keyboard.c: Protect all references to kbd_buffer_frames with

* keyboard.c: Protect all references to kbd_buffer_frames with
	#ifdef MULTI_FRAME.

	* frame.h (struct frame): New fields `can_have_scrollbars' and
	`has_vertical_scrollbars'.
	(FRAME_CAN_HAVE_SCROLLBARS, FRAME_HAS_VERTICAL_SCROLLBARS): New
	accessors, for both the MULTI_FRAME and non-MULTI_FRAME.
	(VERTICAL_SCROLLBAR_WIDTH, WINDOW_VERTICAL_SCROLLBAR,
	WINDOW_VERTICAL_SCROLLBAR_COLUMN,
	WINDOW_VERTICAL_SCROLLBAR_HEIGHT): New macros.
	* window.h (struct window): New field `vertical_scrollbar'.
	* xterm.h (struct x_display): vertical_scrollbars,
	judge_timestamp, vertical_scrollbar_extra: New fields.
	(struct scrollbar): New struct.
	(VERTICAL_SCROLLBAR_PIXEL_WIDTH, VERTICAL_SCROLLBAR_PIXEL_HEIGHT,
	VERTICAL_SCROLLBAR_LEFT_BORDER, VERTICAL_SCROLLBAR_RIGHT_BORDER,
	VERTICAL_SCROLLBAR_TOP_BORDER, VERTICAL_SCROLLBAR_BOTTOM_BORDER,
	CHAR_TO_PIXEL_WIDTH, CHAR_TO_PIXEL_HEIGHT, PIXEL_TO_CHAR_WIDTH,
	PIXEL_TO_CHAR_HEIGHT): New accessors and macros.
	* frame.c (make_frame): Initialize the `can_have_scrollbars' and
	`has_vertical_scrollbars' fields of the frame.
	* term.c (term_init): Note that TERMCAP terminals don't support
	scrollbars.
	(mouse_position_hook): Document new args.
	(set_vertical_scrollbar_hook, condemn_scrollbars_hook,
	redeem_scrollbar_hook, judge_scrollbars_hook): New hooks.
	* termhooks.h: Declare and document them.
	(enum scrollbar_part): New type.
	(struct input_event): Describe the new form of the scrollbar_click
	event type.  Change `part' from a Lisp_Object to an enum
	scrollbar_part.  Add a new field `scrollbar'.
	* keyboard.c (kbd_buffer_get_event): Pass appropriate new
	parameters to *mouse_position_hook, and make_lispy_movement.
	* xfns.c (x_set_vertical_scrollbar): New function.
	(x_figure_window_size): Use new macros to calculate frame size.
	(Fx_create_frame): Note that X Windows frames do support scroll
	bars.  Default to "yes".
	* xterm.c: #include <X11/cursorfont.h> and "window.h".
	(x_vertical_scrollbar_cursor): New variable.
	(x_term_init): Initialize it.
	(last_mouse_bar, last_mouse_bar_frame, last_mouse_part,
	last_mouse_scroll_range_start, last_mouse_scroll_range_end): New
	variables.
	(XTmouse_position): Use them to return scrollbar movement events.
	Take new arguments, for that purpose.
	(x_window_to_scrollbar, x_scrollbar_create,
	x_scrollbar_set_handle, x_scrollbar_remove, x_scrollbar_move,
	XTset_scrollbar, XTcondemn_scrollbars, XTredeem_scrollbar,
	XTjudge_scrollbars, x_scrollbar_expose,
	x_scrollbar_background_expose, x_scrollbar_handle_click,
	x_scrollbar_handle_motion): New functions to implement scrollbars.
	(x_term_init): Set the termhooks.h hooks to point to them.
	(x_set_window_size): Use new macros to calculate frame size.  Set
	vertical_scrollbar_extra field.
	(x_make_frame_visible): Use the frame accessor
	FRAME_HAS_VERTICAL_SCROLLBARS to decide if we need to map the
	frame's subwindows as well.
	(XTread_socket): Use new size-calculation macros from xterm.h when
	processing ConfigureNotify events.
	(x_wm_set_size_hint): Use PIXEL_TO_CHAR_WIDTH and
	PIXEL_TO_CHAR_HEIGHT macros.
	* ymakefile (xdisp.o): This now depends on termhooks.h.
	(xterm.o): This now depends on window.h.

	* keyboard.c (Qscrollbar_movement, Qvertical_scrollbar,
	Qabove_handle, Qhandle, Qbelow_handle): New symbols.
	(make_lispy_event): New code to build scrollbar clicks.
	(make_lispy_movement): New code to handle scrollbar movement.
	(head_table): Include Qscrollbar_movement in the event heads.
	(syms_of_keyboard): Init and staticpro Qvertical_scrollbar,
	Qabove_handle, Qhandle, and Qbelow_handle.
	* keyboard.h (Qscrollbar_movement): Declare this along with the
	other event types.
	* lisp.h (Qvertical_scrollbar): Declare this.
	* window.c (window_from_scrollbar): New function.

	* xterm.h (struct x_display): Delete v_scrollbar, v_thumbup,
	v_thumbdown, v_slider, h_scrollbar, h_thumbup,
	h_thumbdown, h_slider, v_scrollbar_width, h_scrollbar_height
	fields.
	* keyboard.c (Qvscrollbar_part, Qvslider_part, Qvthumbup_part,
	Qvthumbdown_part, Qhscrollbar_part, Qhslider_part, Qhthumbup_part,
	Qhthumbdown_part, Qscrollbar_click): Deleted; part of an obsolete
	interface.
	(head_table): Removed from here as well.
	(syms_of_keyboard): And here.
	* keyboard.h: And here.
	(POSN_SCROLLBAR_BUTTON): Removed.
	* xscrollbar.h: File removed - no longer necessary.
	* xfns.c: Don't #include it any more.
	(Qhorizontal_scroll_bar, Qvertical_scroll_bar): Deleted.
	(syms_of_xfns): Don't initialize or staticpro them.
	(gray_bits): Salvaged from xscrollbar.h.
	(x_window_to_scrollbar): Deleted.
	(x_set_horizontal_scrollbar): Deleted.
	(enum x_frame_parm, x_frame_parms): Remove references to
	x_set_horizontal_scrollbar.
	(x_set_foreground_color, x_set_background_color,
	x_set_border_pixel): Remove special code to support scrollbars.
	(Fx_create_frame): Remove old scrollbar setup code.
	(install_vertical_scrollbar, install_horizontal_scrollbar,
	adjust_scrollbars, x_resize_scrollbars): Deleted.
	* xterm.c (construct_mouse_click): This doesn't need to take care of
	scrollbar clicks anymore.
	(XTread_socket): Remove old code to support scrollbars.  Call new
	functions instead for events which occur in scrollbar windows.
	(XTupdate_end): Remove call to adjust_scrollbars; the main
	redisplay code takes care of that now.
	(enum window_type): Deleted.
	* ymakefile: Note that xfns.o no longer depends on xscrollbar.h.

	* keyboard.c (Fread_key_sequence): Doc fix.

	* keyboard.c (make_lispy_event): Buttons are numbered starting
	with zero now.

	* keyboard.c (make_lispy_event): Use the proper accessors when
	manipulating the `x' and `y' fields of struct input_event.

	* keyboard.c (parse_modifiers_uncached): Remember that strncmp
	returns zero if the two substrings are equal.

	* keyboard.c (do_mouse_tracking, Ftrack_mouse): Doc fix.

	* keyboard.c (read_char): Don't put mouse movements in
	this_command_keys.

	Change the meaning of focus redirection to make switching windows
	work properly.  Fredirect_frame_focus has the details.
	* frame.h (focus_frame): Doc fix.
	[not MULTI_FRAME] (FRAME_FOCUS_FRAME): Make this Qnil, which
	indicates no focus redirection, instead of zero, which is
	selected_frame.
	* frame.c (make_frame): Initialize f->focus_frame to Qnil, rather
	than making it point to frame itself.
	(Fselect_frame): If changing the selected frame from FOO to BAR,
	make all redirections to FOO shift to BAR as well.  Doc fix.
	(Fredirect_frame_focus): Doc fix.  Accept nil as a valid
	redirection, not just as a default for FRAME.
	(Fframe_focus): Doc fix.
	* keyboard.c (kbd_buffer_store_event, kbd_buffer_get_event): Deal
	with focus redirections being nil.
	* xterm.c (XTframe_rehighlight): Doc fix.  Deal with focus
	redirections being nil.

	* keyboard.c (kbd_buffer_frames): New vector, to GCPRO frames in
	kbd_buffer.
	(kbd_buffer_store_event): When we add an event to kbd_buffer, make
	sure to store its frame in kbd_buffer_frames.
	(kbd_buffer_get_event): When we remove an event from kbd_buffer,
	make sure to set the corresponding element of kbd_buffer_frames to
	Qnil, to allow the frame to get GC'd.
	(Fdiscard_input, init_keyboard): Clear all elements of
	kbd_buffer_frames to nil.
	(syms_of_keyboard): Create and staticpro kbd_buffer_frames.