* src/w32fns.c (w32_fullscreen_rect): New function to compute the

* src/w32fns.c (w32_fullscreen_rect): New function to compute the
window rectangle for the given fullscreen mode.
(w32_wnd_proc): When in a fullscreen mode, WM_WINDOWPOSCHANGING
no longer tunes the window size.  This keeps the window's edges
flush with the screen and allows the taskbar to hide itself in
fullboth.
* src/w32term.c (w32fullscreen_hook): fullboth now shows without
window decorations and uses the entire screen.