Added a GTK3-safe null guard before unrefing cursors while keeping GTK2 behavior under !HAVE_GTK3.

Added a GTK3 pointer-device null fallback in gtk_xtext_get_pointer to safely handle missing devices before using gdk_device_get_position.

src/fe-gtk/xtext.c

@@ -156,6 +156,8 @@ gtk_xtext_cursor_unref (GdkCursor *cursor)
 #if !HAVE_GTK3
 	gdk_cursor_unref (cursor);
 #else
+	if (!cursor)
+		return;
 	g_object_unref (cursor);
 #endif
 }
@@ -746,6 +748,17 @@ gtk_xtext_get_pointer (GdkWindow *window, gint *x, gint *y, GdkModifierType *mas
 	gint win_x = 0;
 	gint win_y = 0;
 
+	if (!device)
+	{
+		if (x)
+			*x = 0;
+		if (y)
+			*y = 0;
+		if (mask)
+			*mask = 0;
+		return;
+	}
+
 	gdk_device_get_position (device, &screen, &root_x, &root_y);
 	gdk_window_get_origin (window, &win_x, &win_y);