SDL: SDL_UDEV_DelCallback: return early if _this is NULL (6dc96)

SDL Commits
1 
From 6dc96aa7455d00a3556618a4a459851424ae5d44 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Fri, 18 Nov 2022 18:02:10 +0300
Subject: [PATCH] SDL_UDEV_DelCallback: return early if _this is NULL

Fixes https://github.com/libsdl-org/SDL/issues/6548
---
 src/core/linux/SDL_udev.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/core/linux/SDL_udev.c b/src/core/linux/SDL_udev.c
index 311cdd1ebe8e..85cde8959607 100644
--- a/src/core/linux/SDL_udev.c
+++ b/src/core/linux/SDL_udev.c
@@ -545,6 +545,10 @@ SDL_UDEV_DelCallback(SDL_UDEV_Callback cb)
     SDL_UDEV_CallbackList *item;
     SDL_UDEV_CallbackList *prev = NULL;
 
+    if (_this == NULL) {
+        return;
+    }
+
     for (item = _this->first; item != NULL; item = item->next) {
         /* found it, remove it. */
         if (item->callback == cb) {