sdl12-compat: remove an unnecessary definition

From fd7220440bd2aa2618ad5fd59bf83b3105f02915 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Wed, 3 Mar 2021 05:51:20 +0300
Subject: [PATCH] remove an unnecessary definition

---
 src/SDL20_include_wrapper.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/SDL20_include_wrapper.h b/src/SDL20_include_wrapper.h
index 7098a39..fccea3a 100644
--- a/src/SDL20_include_wrapper.h
+++ b/src/SDL20_include_wrapper.h
@@ -113,9 +113,7 @@
 
 /* Missing SDL_thread.h stuff (see above): */
 #if defined(_WIN32) || defined(__OS2__)
-struct SDL_Thread;
 typedef struct SDL_Thread SDL_Thread;
-typedef unsigned long SDL_threadID;
 typedef int (SDLCALL *SDL_ThreadFunction) (void*);
 #endif
 #ifdef __OS2__