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, 1 deletions

diff --git a/src/pgtkterm.c b/src/pgtkterm.c
index 2da1006b6f7..0f272bbeac8 100644
--- a/src/pgtkterm.c
+++ b/src/pgtkterm.c
@@ -5938,7 +5938,6 @@ motion_notify_event (GtkWidget *widget, GdkEvent *event,
              also when the target window is on another frame.  */
           && (f == XFRAME (selected_frame) || !NILP (focus_follows_mouse)))
         {
-          static Lisp_Object last_mouse_window;
           Lisp_Object window = window_from_coordinates
             (f, event->motion.x, event->motion.y, 0, false, false, false);