Protect against GCing of last_mouse_window

* src/window.c (last_mouse_window): New global var.  All static
instances removed, and all their uses replaced with this global
var.  This fixes a very unlikely bug where last_mouse_window was
GC’ed and a new window created in its place.  It also fixes several
places that assumed NIL_IS_ZERO without static_asserting it.
(init_window_once): Initialize the new var.

1 files changed, 0 insertions, 2 deletions

diff --git a/src/msdos.c b/src/msdos.c
index 95eb6453040..49403ba72f4 100644
--- a/src/msdos.c
+++ b/src/msdos.c
@@ -2677,8 +2677,6 @@ dos_rawgetc (void)
           /* Generate SELECT_WINDOW_EVENTs when needed.  */
           if (!NILP (Vmouse_autoselect_window))
             {
-              static Lisp_Object last_mouse_window;
-
               mouse_window = window_from_coordinates
                 (SELECTED_FRAME (), mouse_last_x, mouse_last_y, 0, 0, 0, 0);
               /* A window will be selected only when it is not