server_client_set_flags
server_client_set_flags(c, fflag);
server_client_set_flags(c, args_get(args, 'f'));
server_client_set_flags(tc, args_get(args, 'F'));
server_client_set_flags(tc, args_get(args, 'f'));
void server_client_set_flags(struct client *, const char *);