Additional harness ideas

[woodruffw]

Consolidating this into a single issue.

• [ ] macOS's security verify-cert: #275
• [ ] NSS: https://github.com/nss-dev/nss
• [ ] Other OpenSSL forks: BoringSSL, LibreSSL
• [x] GnuTLS (#240)
• [ ] WolfSSL
• [ ] BearSSL
• [ ] Bouncy Castle
• [ ] Botan: https://botan.randombit.net/
• [ ] Mbed TLS
  • Relevant API: mbedtls_x509_crt_verify_with_profile: https://mbed-tls.readthedocs.io/projects/api/en/development/api/group/group__x509__module/#group__x509__module_1gaf044a51e5b5bc854bf12aeeccb440e55
• [ ] s2n
• [x] certvalidator: https://github.com/wbond/certvalidator/blob/master/docs/api.md
• [ ] swift-certificates: https://github.com/apple/swift-certificates
• [ ] Others?

[woodruffw]

NTS: Given CVE-2024-0567, GnuTLS is a high-ish priority harness to add.

[mschwager]

Here's a fun one: https://github.com/guanzhi/GmSSL