client_windows
return (RB_FIND(client_windows, &c->windows, &cw));
RB_INSERT(client_windows, &c->windows, cw);
RB_REMOVE(client_windows, &c->windows, cw);
RB_FOREACH_SAFE(cw, client_windows, &c->windows, cw1) {
RB_REMOVE(client_windows, &c->windows, cw);
RB_GENERATE(client_windows, client_window, entry, server_client_window_cmp);
struct client_windows windows;