Update SDL2 to newest version to fix 7.1 playback

This fixes 7.1 playback. Before this commit, SDL used 7.1 front audio configuration with Center Left and Center Right speakers, but without Rear speakers.

See https://github.com/libsdl-org/SDL/issues/11709 for more details.

libs/SDL2/include/SDL_thread.h

@@ -1,6 +1,6 @@
 /*
   Simple DirectMedia Layer
-  Copyright (C) 1997-2023 Sam Lantinga <slouken@libsdl.org>
+  Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>
 
   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
@@ -23,9 +23,9 @@
 #define SDL_thread_h_
 
 /**
- *  \file SDL_thread.h
+ * # CategoryThread
  *
- *  Header for the SDL thread management routines.
+ * Header for the SDL thread management routines.
  */
 
 #include "SDL_stdinc.h"
@@ -63,16 +63,18 @@ typedef unsigned long SDL_threadID;
 typedef unsigned int SDL_TLSID;
 
 /**
- *  The SDL thread priority.
+ * The SDL thread priority.
  *
- *  SDL will make system changes as necessary in order to apply the thread priority.
- *  Code which attempts to control thread state related to priority should be aware
- *  that calling SDL_SetThreadPriority may alter such state.
- *  SDL_HINT_THREAD_PRIORITY_POLICY can be used to control aspects of this behavior.
+ * SDL will make system changes as necessary in order to apply the thread
+ * priority. Code which attempts to control thread state related to priority
+ * should be aware that calling SDL_SetThreadPriority may alter such state.
+ * SDL_HINT_THREAD_PRIORITY_POLICY can be used to control aspects of this
+ * behavior.
  *
- *  \note On many systems you require special privileges to set high or time critical priority.
+ * On many systems you require special privileges to set high or time critical
+ * priority.
  */
-typedef enum {
+typedef enum SDL_ThreadPriority {
     SDL_THREAD_PRIORITY_LOW,
     SDL_THREAD_PRIORITY_NORMAL,
     SDL_THREAD_PRIORITY_HIGH,
@@ -82,7 +84,7 @@ typedef enum {
 /**
  * The function passed to SDL_CreateThread().
  *
- * \param data what was passed as `data` to SDL_CreateThread()
+ * \param data what was passed as `data` to SDL_CreateThread().
  * \returns a value that can be reported through SDL_WaitThread().
  */
 typedef int (SDLCALL * SDL_ThreadFunction) (void *data);
@@ -192,9 +194,9 @@ SDL_CreateThreadWithStackSize(SDL_ThreadFunction fn, const char *name, const siz
  * SDL_CreateThreadWithStackSize(fn, name, 0, data);
  * ```
  *
- * \param fn the SDL_ThreadFunction function to call in the new thread
- * \param name the name of the thread
- * \param data a pointer that is passed to `fn`
+ * \param fn the SDL_ThreadFunction function to call in the new thread.
+ * \param name the name of the thread.
+ * \param data a pointer that is passed to `fn`.
  * \returns an opaque pointer to the new thread object on success, NULL if the
  *          new thread could not be created; call SDL_GetError() for more
  *          information.
@@ -238,10 +240,10 @@ SDL_CreateThread(SDL_ThreadFunction fn, const char *name, void *data);
  * function, but for backwards compatibility, this is currently a separate
  * function.
  *
- * \param fn the SDL_ThreadFunction function to call in the new thread
- * \param name the name of the thread
+ * \param fn the SDL_ThreadFunction function to call in the new thread.
+ * \param name the name of the thread.
  * \param stacksize the size, in bytes, to allocate for the new thread stack.
- * \param data a pointer that is passed to `fn`
+ * \param data a pointer that is passed to `fn`.
  * \returns an opaque pointer to the new thread object on success, NULL if the
  *          new thread could not be created; call SDL_GetError() for more
  *          information.
@@ -261,7 +263,7 @@ SDL_CreateThreadWithStackSize(SDL_ThreadFunction fn, const char *name, const siz
  * This is internal memory, not to be freed by the caller, and remains valid
  * until the specified thread is cleaned up by SDL_WaitThread().
  *
- * \param thread the thread to query
+ * \param thread the thread to query.
  * \returns a pointer to a UTF-8 string that names the specified thread, or
  *          NULL if it doesn't have a name.
  *
@@ -296,7 +298,7 @@ extern DECLSPEC SDL_threadID SDLCALL SDL_ThreadID(void);
  * If SDL is running on a platform that does not support threads the return
  * value will always be zero.
  *
- * \param thread the thread to query
+ * \param thread the thread to query.
  * \returns the ID of the specified thread, or the ID of the current thread if
  *          `thread` is NULL.
  *
@@ -313,7 +315,7 @@ extern DECLSPEC SDL_threadID SDLCALL SDL_GetThreadID(SDL_Thread * thread);
  * promote the thread to a higher priority) at all, and some require you to be
  * an administrator account. Be prepared for this to fail.
  *
- * \param priority the SDL_ThreadPriority to set
+ * \param priority the SDL_ThreadPriority to set.
  * \returns 0 on success or a negative error code on failure; call
  *          SDL_GetError() for more information.
  *
@@ -344,7 +346,7 @@ extern DECLSPEC int SDLCALL SDL_SetThreadPriority(SDL_ThreadPriority priority);
  * afterward.
  *
  * \param thread the SDL_Thread pointer that was returned from the
- *               SDL_CreateThread() call that started this thread
+ *               SDL_CreateThread() call that started this thread.
  * \param status pointer to an integer that will receive the value returned
  *               from the thread function by its 'return', or NULL to not
  *               receive such value back.
@@ -383,7 +385,7 @@ extern DECLSPEC void SDLCALL SDL_WaitThread(SDL_Thread * thread, int *status);
  * It is safe to pass NULL to this function; it is a no-op.
  *
  * \param thread the SDL_Thread pointer that was returned from the
- *               SDL_CreateThread() call that started this thread
+ *               SDL_CreateThread() call that started this thread.
  *
  * \since This function is available since SDL 2.0.2.
  *
@@ -410,7 +412,7 @@ extern DECLSPEC SDL_TLSID SDLCALL SDL_TLSCreate(void);
 /**
  * Get the current thread's value associated with a thread local storage ID.
  *
- * \param id the thread local storage ID
+ * \param id the thread local storage ID.
  * \returns the value associated with the ID for the current thread or NULL if
  *          no value has been set; call SDL_GetError() for more information.
  *
@@ -421,6 +423,8 @@ extern DECLSPEC SDL_TLSID SDLCALL SDL_TLSCreate(void);
  */
 extern DECLSPEC void * SDLCALL SDL_TLSGet(SDL_TLSID id);
 
+typedef void (SDLCALL *SDL_TLSDestructorCallback)(void*);
+
 /**
  * Set the current thread's value associated with a thread local storage ID.
  *
@@ -432,10 +436,10 @@ extern DECLSPEC void * SDLCALL SDL_TLSGet(SDL_TLSID id);
  *
  * where its parameter `value` is what was passed as `value` to SDL_TLSSet().
  *
- * \param id the thread local storage ID
- * \param value the value to associate with the ID for the current thread
+ * \param id the thread local storage ID.
+ * \param value the value to associate with the ID for the current thread.
  * \param destructor a function called when the thread exits, to free the
- *                   value
+ *                   value.
  * \returns 0 on success or a negative error code on failure; call
  *          SDL_GetError() for more information.
  *
@@ -444,7 +448,7 @@ extern DECLSPEC void * SDLCALL SDL_TLSGet(SDL_TLSID id);
  * \sa SDL_TLSCreate
  * \sa SDL_TLSGet
  */
-extern DECLSPEC int SDLCALL SDL_TLSSet(SDL_TLSID id, const void *value, void (SDLCALL *destructor)(void*));
+extern DECLSPEC int SDLCALL SDL_TLSSet(SDL_TLSID id, const void *value, SDL_TLSDestructorCallback destructor);
 
 /**
  * Cleanup all TLS data for this thread.