SDL: Fixed crash if num_mime_types is NULL

SDL Commits
1 
From 196e2c666220a82a1ecb474bee46983134c2b9ba Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Tue, 31 Dec 2024 12:02:43 -0800
Subject: [PATCH] Fixed crash if num_mime_types is NULL

---
 src/video/SDL_clipboard.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/video/SDL_clipboard.c b/src/video/SDL_clipboard.c
index 93493673585ab..c5f06974795d6 100644
--- a/src/video/SDL_clipboard.c
+++ b/src/video/SDL_clipboard.c
@@ -284,12 +284,18 @@ char **SDL_GetClipboardMimeTypes(size_t *num_mime_types)
 {
     SDL_VideoDevice *_this = SDL_GetVideoDevice();
 
+    if (num_mime_types) {
+        *num_mime_types = 0;
+    }
+
     if (!_this) {
-        SDL_SetError("Video subsystem must be initialized to query clipboard mime types");
+        SDL_SetError("Video subsystem has not been initialized");
         return NULL;
     }
 
-    *num_mime_types = _this->num_clipboard_mime_types;
+    if (num_mime_types) {
+        *num_mime_types = _this->num_clipboard_mime_types;
+    }
     return SDL_CopyClipboardMimeTypes((const char **)_this->clipboard_mime_types, _this->num_clipboard_mime_types, false);
 }