SDL: Fixed crash if display couldn't be found in SDL_UpdateFullscreenMode()

SDL Commits
1 
From 4c0758a234658a0f48a56d2263c744aaa9cee898 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Thu, 8 Jun 2023 12:39:32 -0700
Subject: [PATCH] Fixed crash if display couldn't be found in
 SDL_UpdateFullscreenMode()

---
 src/video/SDL_video.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
index b9496d72eb38..01278ec88666 100644
--- a/src/video/SDL_video.c
+++ b/src/video/SDL_video.c
@@ -1462,6 +1462,10 @@ static int SDL_UpdateFullscreenMode(SDL_Window *window, SDL_bool fullscreen)
     /* Get the correct display for this operation */
     if (fullscreen) {
         display = SDL_GetVideoDisplayForWindow(window);
+        if (!display) {
+            /* This should never happen, but it did... */
+            goto done;
+        }
     } else {
         for (i = 0; i < _this->num_displays; ++i) {
             display = &_this->displays[i];