screen_write_vnputs
screen_write_vnputs(ctx, -1, gcp, fmt, ap);
screen_write_vnputs(ctx, maxlen, gcp, fmt, ap);
void printflike(4, 0) screen_write_vnputs(struct screen_write_ctx *, ssize_t,
screen_write_vnputs(&backing_ctx, 0, &gc, fmt, ap);