Free a set of sockets allocated by SDLNet_AllocSocketSet().
void SDLNet_FreeSocketSet(SDLNet_SocketSet set);
the socket set to free.
When done with a socket set, call this function to free its resources.
This only frees the socket set, not the individual sockets in the set, which would still (at some future point) need to be closed with SDLNet_TCP_Close or SDLNet_UDP_Close.
This function is available since SDL_net 2.0.0.