sdl2-compat: fix build using c++ compilers.

SDL Commits
1 
From f56d4f9559dd4fb84fefd5c84a1a8cfea4ba0e1e Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Fri, 31 Jan 2025 06:04:20 +0300
Subject: [PATCH] fix build using c++ compilers.

---
 src/sdl2_compat.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/sdl2_compat.c b/src/sdl2_compat.c
index 58a2182..0b5a5fe 100644
--- a/src/sdl2_compat.c
+++ b/src/sdl2_compat.c
@@ -5672,11 +5672,11 @@ static void SDLCALL SDL2AudioDeviceCallbackBridge(void *userdata, SDL_AudioStrea
             const int br = SDL_AudioStreamGet(stream2, stream2->callback2_buffer, stream2->bytes_per_callbacks);
             SDL_assert(br == stream2->bytes_per_callbacks);
             approx_amount -= br;
-            stream2->callback2(stream2->callback2_userdata, stream2->callback2_buffer, br);
+            stream2->callback2(stream2->callback2_userdata, (Uint8 *) stream2->callback2_buffer, br);
         }
     } else {
         while (approx_amount > 0) {
-            stream2->callback2(stream2->callback2_userdata, stream2->callback2_buffer, stream2->bytes_per_callbacks);
+            stream2->callback2(stream2->callback2_userdata, (Uint8 *) stream2->callback2_buffer, stream2->bytes_per_callbacks);
             SDL_AudioStreamPut(stream2, stream2->callback2_buffer, stream2->bytes_per_callbacks);
             approx_amount -= stream2->bytes_per_callbacks;
             if (approx_amount < 0) {