sdl2-compat: fix build after SDL_atomic_t rename to SDL_AtomicInt

From 28bff9413c374798314301204faaa98399aac29e Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Thu, 9 Mar 2023 20:56:32 +0300
Subject: [PATCH] fix build after SDL_atomic_t rename to SDL_AtomicInt

---
 src/sdl2_compat.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/sdl2_compat.h b/src/sdl2_compat.h
index cc7a2f2..f8540ee 100644
--- a/src/sdl2_compat.h
+++ b/src/sdl2_compat.h
@@ -24,6 +24,8 @@
 
 /* these types were removed from SDL3, but we need them for SDL2 APIs exported here. */
 
+typedef SDL_AtomicInt SDL_atomic_t;
+
 typedef SDL_Gamepad SDL_GameController;  /* since they're opaque types, for simplicity we just typedef it here and use the old types in sdl3_syms.h */
 typedef SDL_GamepadAxis SDL_GameControllerAxis;
 typedef SDL_GamepadBinding SDL_GameControllerButtonBind;