get0_best_issuer_sk
issuer = (X509_self_signed(curr, 0) > 0 || num > max_depth) ? NULL : get0_best_issuer_sk(ctx, 0, 1 /* no_dup */, sk_untrusted, curr);
*issuer = get0_best_issuer_sk(ctx, 0, 0 /* allow duplicates */, certs, x);
*issuer = get0_best_issuer_sk(ctx, 0, 1 /* no_dup */, ctx->other_ctx, x);