cert_parse_ta
struct cert *cert_parse_ta(const char *, const unsigned char *, size_t,
cert = cert_parse_ta(file, f, flen, tal->spki, tal->spkisz);
cert2 = cert_parse_ta(file2, der, der_len, spki, spkisz);
cert1 = cert_parse_ta(file1, der, der_len, spki, spkisz);