freebsd11_cvtnstat
error = freebsd11_cvtnstat(sb, &nsb);
error = freebsd11_cvtnstat(&ub, &nub);
error = freebsd11_cvtnstat(&sb, &nsb);
error = freebsd11_cvtnstat(&sb, &nsb);
int freebsd11_cvtnstat(struct stat *sb, struct nstat *nsb);