static int plug_proxy_closing (Plug p, char *error_msg,
static int plug_proxy_closing (Plug p, const char *error_msg,
static int plug_proxy_closing (Plug p, char *error_msg,			       int error_code, int calling_back){    Proxy_Plug pp = (Proxy_Plug) p;    Proxy_Socket ps = pp->proxy_socket;    if (ps->state != PROXY_STATE_ACTIVE) {	ps->closing_error_msg = error_msg;	ps->closing_error_code = error_code;	ps->closing_calling_back = calling_back;	return ps->negotiate(ps, PROXY_CHANGE_CLOSING);    }    return plug_closing(ps->plug, error_msg,			error_code, calling_back);}