Patched to compile on C89 compilers.

src/audio/SDL_audio.c

@@ -687,8 +687,9 @@ SDL_RunAudio(void *devicep)
             SDL_AudioStreamPut(device->stream, data, data_len);
 
             while (SDL_AudioStreamAvailable(device->stream) >= ((int) device->spec.size)) {
+                int got;
                 data = SDL_AtomicGet(&device->enabled) ? current_audio.impl.GetDeviceBuf(device) : NULL;
-                const int got = SDL_AudioStreamGet(device->stream, data ? data : device->work_buffer, device->spec.size);
+                got = SDL_AudioStreamGet(device->stream, data ? data : device->work_buffer, device->spec.size);
                 SDL_assert((got < 0) || (got == device->spec.size));
 
                 if (data == NULL) {  /* device is having issues... */