(SIF_*): Win95 macros defined for NT.

(SIF_*): Win95 macros defined for NT.
(struct tagSCROLLINFO): Win95 struct defined for NT.
(vertical_scroll_bar_min_handle, vertical_scroll_bar_top_border,
vertical_scroll_bar_bottom_border, last_scroll_bar_drag_pos,
Vw32_gab_focus_on_raise, Vw32_capslock_is_shiftlock): New
variables.
(w32_frame_up_to_date): Block input.
(do_line_dance): Use DC while erasing, release at end.
(show_mouse_face): Use column and endcolumn calculated at start of
loop.
(my_create_scrollbar, my_show_window, my_set_window_pos,
my_set_focus) [! ATTACH_THREADS]: Send message to window instead
of invoking Windows procedure.
(x_scroll_bar_create, x_scroll_bar_move, x_scroll_bar_handle_click,
x_scroll_bar_report_motion): Use SCROLLINFO for proportional handle.
(x_scroll_bar_set_handle): Create proportional sized scroll handle.
(w32_set_vertical_scroll_bar): Size handle according to how much
is showing in window.
(x_scroll_bar_set_report_motion): Use top_range, calculated above.
(x_scroll_bar_clear): Hide scroll bar until ready to repaint.
(show_scroll_bars): Pass in frame to my_show_window.
(w32_read_socket): Distinguish between invisible and obscured frames
when handling PAINT messages.
Fixup off-by-one calculation for PAINT and SIZE.
Pass in new parameter to w32_kbd_mods_to_emacs.
Handle WM_DISPLAYCHANGE, WINDOWPOSCHANGED, ACTIVATE, SHOWWINDOW,
INITMENU, and ACTIVATEAPP messages.
Explicitly check for visibile and obscured frames, and to see if
any event should cause a redisplay.

(x_display_bar_cursor): Don't check whether frame is updating here.
(x_display_cursor): Check it here instead.
(x_set_offset) [HAVE_NTGUI]: Don't add border widths.
Set NOACTIVATE when setting window position.
(x_set_window_size): Fixup off-by-one calculation when setting
window position.  Mark frame garbaged earlier.  Clear mouse
highlighting state.
(x_focus_on_frame): Set focus by making frame the foreground window.
(x_raise_frame): Support frames to be raised without grabbing focus.
(x_lower_frame): Set NOACTIVATE flag when setting window position.
(x_make_frame_visible, x_make_frame_invisible): Pass in frame
to my_show_window.
to my_show_window.
(x_iconify_frame): Send a MINIMIZE message to the window.
(x_wm_set_size_hint): Set font width, line height, border,
and scroll bar indexes instead of X and Y unit indexes.

(w32_initialize): Set input mode.  Use w32_msg_worker instead
of windows_msg_worker.  Dynamically link proportional scroll bar
functions and intialize proportional scroll bar variables.
(syms_of_w32term): DEFVAR new variables.

(construct_mouse_wheel): New function.  Constructs an
input event from a WM_MOUSEWHEEL message.
(w32_read_socket): Handle WM_MOUSEWHEEL.

(w32_read_socket): Pass in new parameter to key_event.
Let key_event determine whether key is dead.
For MOVE, use x_real_positions to map to client coords.
(x_set_mouse_pixel_position): Offset to use client area as origin.