SDL: wayland: Null all Wayland manager objects after freeing

SDL Commits
1 
From 4454dc400b8618a9009898e17e8c937bf3e811a2 Mon Sep 17 00:00:00 2001
From: Frank Praznik <[EMAIL REDACTED]>
Date: Tue, 26 Sep 2023 11:18:52 -0400
Subject: [PATCH] wayland: Null all Wayland manager objects after freeing

---
 src/video/wayland/SDL_waylandvideo.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/video/wayland/SDL_waylandvideo.c b/src/video/wayland/SDL_waylandvideo.c
index 2ba3bb7f3c61..bd9b7d4041a4 100644
--- a/src/video/wayland/SDL_waylandvideo.c
+++ b/src/video/wayland/SDL_waylandvideo.c
@@ -946,10 +946,12 @@ static void Wayland_VideoCleanup(SDL_VideoDevice *_this)
 
     if (data->pointer_constraints) {
         zwp_pointer_constraints_v1_destroy(data->pointer_constraints);
+        data->pointer_constraints = NULL;
     }
 
     if (data->relative_pointer_manager) {
         zwp_relative_pointer_manager_v1_destroy(data->relative_pointer_manager);
+        data->relative_pointer_manager = NULL;
     }
 
     if (data->activation_manager) {