OpenSSL::Netscape::SPKI#to_text

static VALUE
ossl_spki_print(VALUE self)
{
    NETSCAPE_SPKI *spki;
    BIO *out;

    GetSPKI(self, spki);
    if (!(out = BIO_new(BIO_s_mem()))) {
        ossl_raise(eSPKIError, NULL);
    }
    if (!NETSCAPE_SPKI_print(out, spki)) {
        BIO_free(out);
        ossl_raise(eSPKIError, NULL);
    }

    return ossl_membio2str(out);
}