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_mouse.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
@@ -20,9 +20,9 @@
 */
 
 /**
- *  \file SDL_mouse.h
+ * # CategoryMouse
  *
- *  Include file for SDL mouse event handling.
+ * Include file for SDL mouse event handling.
  */
 
 #ifndef SDL_mouse_h_
@@ -41,9 +41,9 @@ extern "C" {
 typedef struct SDL_Cursor SDL_Cursor;   /**< Implementation dependent */
 
 /**
- * \brief Cursor types for SDL_CreateSystemCursor().
+ * Cursor types for SDL_CreateSystemCursor().
  */
-typedef enum
+typedef enum SDL_SystemCursor
 {
     SDL_SYSTEM_CURSOR_ARROW,     /**< Arrow */
     SDL_SYSTEM_CURSOR_IBEAM,     /**< I-beam */
@@ -61,9 +61,9 @@ typedef enum
 } SDL_SystemCursor;
 
 /**
- * \brief Scroll direction types for the Scroll event
+ * Scroll direction types for the Scroll event
  */
-typedef enum
+typedef enum SDL_MouseWheelDirection
 {
     SDL_MOUSEWHEEL_NORMAL,    /**< The scroll direction is normal */
     SDL_MOUSEWHEEL_FLIPPED    /**< The scroll direction is flipped / natural */
@@ -90,9 +90,9 @@ extern DECLSPEC SDL_Window * SDLCALL SDL_GetMouseFocus(void);
  * either `x` or `y`.
  *
  * \param x the x coordinate of the mouse cursor position relative to the
- *          focus window
+ *          focus window.
  * \param y the y coordinate of the mouse cursor position relative to the
- *          focus window
+ *          focus window.
  * \returns a 32-bit button bitmask of the current button state.
  *
  * \since This function is available since SDL 2.0.0.
@@ -120,9 +120,9 @@ extern DECLSPEC Uint32 SDLCALL SDL_GetMouseState(int *x, int *y);
  * reason to use this function, you probably want SDL_GetMouseState() instead.
  *
  * \param x filled in with the current X coord relative to the desktop; can be
- *          NULL
+ *          NULL.
  * \param y filled in with the current Y coord relative to the desktop; can be
- *          NULL
+ *          NULL.
  * \returns the current button state as a bitmask which can be tested using
  *          the SDL_BUTTON(X) macros.
  *
@@ -141,8 +141,8 @@ extern DECLSPEC Uint32 SDLCALL SDL_GetGlobalMouseState(int *x, int *y);
  * mouse deltas since the last call to SDL_GetRelativeMouseState() or since
  * event initialization. You can pass NULL for either `x` or `y`.
  *
- * \param x a pointer filled with the last recorded x coordinate of the mouse
- * \param y a pointer filled with the last recorded y coordinate of the mouse
+ * \param x a pointer filled with the last recorded x coordinate of the mouse.
+ * \param y a pointer filled with the last recorded y coordinate of the mouse.
  * \returns a 32-bit button bitmask of the relative button state.
  *
  * \since This function is available since SDL 2.0.0.
@@ -162,9 +162,9 @@ extern DECLSPEC Uint32 SDLCALL SDL_GetRelativeMouseState(int *x, int *y);
  * mouse when used over Microsoft Remote Desktop.
  *
  * \param window the window to move the mouse into, or NULL for the current
- *               mouse focus
- * \param x the x coordinate within the window
- * \param y the y coordinate within the window
+ *               mouse focus.
+ * \param x the x coordinate within the window.
+ * \param y the y coordinate within the window.
  *
  * \since This function is available since SDL 2.0.0.
  *
@@ -184,8 +184,8 @@ extern DECLSPEC void SDLCALL SDL_WarpMouseInWindow(SDL_Window * window,
  * Note that this function will appear to succeed, but not actually move the
  * mouse when used over Microsoft Remote Desktop.
  *
- * \param x the x coordinate
- * \param y the y coordinate
+ * \param x the x coordinate.
+ * \param y the y coordinate.
  * \returns 0 on success or a negative error code on failure; call
  *          SDL_GetError() for more information.
  *
@@ -297,14 +297,14 @@ extern DECLSPEC SDL_bool SDLCALL SDL_GetRelativeMouseMode(void);
  * Also, since SDL 2.0.0, SDL_CreateSystemCursor() is available, which
  * provides twelve readily available system cursors to pick from.
  *
- * \param data the color value for each pixel of the cursor
- * \param mask the mask value for each pixel of the cursor
- * \param w the width of the cursor
- * \param h the height of the cursor
+ * \param data the color value for each pixel of the cursor.
+ * \param mask the mask value for each pixel of the cursor.
+ * \param w the width of the cursor.
+ * \param h the height of the cursor.
  * \param hot_x the X-axis location of the upper left corner of the cursor
- *              relative to the actual mouse position
+ *              relative to the actual mouse position.
  * \param hot_y the Y-axis location of the upper left corner of the cursor
- *              relative to the actual mouse position
+ *              relative to the actual mouse position.
  * \returns a new cursor with the specified parameters on success or NULL on
  *          failure; call SDL_GetError() for more information.
  *
@@ -322,9 +322,9 @@ extern DECLSPEC SDL_Cursor *SDLCALL SDL_CreateCursor(const Uint8 * data,
 /**
  * Create a color cursor.
  *
- * \param surface an SDL_Surface structure representing the cursor image
- * \param hot_x the x position of the cursor hot spot
- * \param hot_y the y position of the cursor hot spot
+ * \param surface an SDL_Surface structure representing the cursor image.
+ * \param hot_x the x position of the cursor hot spot.
+ * \param hot_y the y position of the cursor hot spot.
  * \returns the new cursor on success or NULL on failure; call SDL_GetError()
  *          for more information.
  *
@@ -340,7 +340,7 @@ extern DECLSPEC SDL_Cursor *SDLCALL SDL_CreateColorCursor(SDL_Surface *surface,
 /**
  * Create a system cursor.
  *
- * \param id an SDL_SystemCursor enum value
+ * \param id an SDL_SystemCursor enum value.
  * \returns a cursor on success or NULL on failure; call SDL_GetError() for
  *          more information.
  *
@@ -358,7 +358,7 @@ extern DECLSPEC SDL_Cursor *SDLCALL SDL_CreateSystemCursor(SDL_SystemCursor id);
  * the display. SDL_SetCursor(NULL) can be used to force cursor redraw, if
  * this is desired for any reason.
  *
- * \param cursor a cursor to make active
+ * \param cursor a cursor to make active.
  *
  * \since This function is available since SDL 2.0.0.
  *
@@ -402,7 +402,7 @@ extern DECLSPEC SDL_Cursor *SDLCALL SDL_GetDefaultCursor(void);
  * Use this function to free cursor resources created with SDL_CreateCursor(),
  * SDL_CreateColorCursor() or SDL_CreateSystemCursor().
  *
- * \param cursor the cursor to free
+ * \param cursor the cursor to free.
  *
  * \since This function is available since SDL 2.0.0.
  *
@@ -437,9 +437,9 @@ extern DECLSPEC int SDLCALL SDL_ShowCursor(int toggle);
 /**
  * Used as a mask when testing buttons in buttonstate.
  *
- * - Button 1:  Left mouse button
- * - Button 2:  Middle mouse button
- * - Button 3:  Right mouse button
+ * - Button 1: Left mouse button
+ * - Button 2: Middle mouse button
+ * - Button 3: Right mouse button
  */
 #define SDL_BUTTON(X)       (1 << ((X)-1))
 #define SDL_BUTTON_LEFT     1