Removed temporary memory from the API

It was intended to make the API easier to use, but various automatic garbage collection all had flaws, and making the application periodically clean up temporary memory added cognitive load to using the API, and in many cases was it was difficult to restructure threaded code to handle this.

So, we're largely going back to the original system, where the API returns allocated results and you free them.

In addition, to solve the problems we originally wanted temporary memory for:
* Short strings with a finite count, like device names, get stored in a per-thread string pool.
* Events continue to use temporary memory internally, which is cleaned up on the next event processing cycle.

include/SDL3/SDL_locale.h

@@ -92,11 +92,11 @@ typedef struct SDL_Locale
  * \param count a pointer filled in with the number of locales returned, may
  *              be NULL.
  * \returns a NULL terminated array of locale pointers, or NULL on failure;
- *          call SDL_GetError() for more information.
+ *          call SDL_GetError() for more information. This is a single allocation that should be freed with SDL_free() when it is no longer needed.
  *
  * \since This function is available since SDL 3.0.0.
  */
-extern SDL_DECLSPEC_TEMP const SDL_Locale * const * SDLCALL SDL_GetPreferredLocales(int *count);
+extern SDL_DECLSPEC_FREE SDL_Locale ** SDLCALL SDL_GetPreferredLocales(int *count);
 
 /* Ends C function definitions when using C++ */
 #ifdef __cplusplus