SDL: Fixed build (c07b3)

SDL Commits
1 
From c07b39fa0663f620bb05ce20de6a02a4dc447237 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Wed, 6 Mar 2024 09:57:27 -0800
Subject: [PATCH] Fixed build

---
 test/testmessage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/testmessage.c b/test/testmessage.c
index 2b8e39439102..e81bcda02f87 100644
--- a/test/testmessage.c
+++ b/test/testmessage.c
@@ -183,7 +183,7 @@ int main(int argc, char *argv[])
         int status = 0;
         SDL_Event event;
         Uint32 eventNumber = SDL_RegisterEvents(1);
-        SDL_Thread *thread = SDL_CreateThread(&button_messagebox, "MessageBox", (void *)eventNumber);
+        SDL_Thread *thread = SDL_CreateThread(&button_messagebox, "MessageBox", (void *)(uintptr_t)eventNumber);
 
         while (SDL_WaitEvent(&event)) {
             if (event.type == eventNumber) {