Few doubts about Boring and certificates

I am using ([a fork of](https://github.com/4JX/boring)) boring in a project of mine and I'm having some trouble with making it use the correct certificates

1. On my Windows machine I am encountering the error `unable to get local issuer certificate`. Reading up on a similar issue in `rust-openssl`, I tried to find a way to set the env var `SSL_CERT_DIR` to a path to the system's certificate store, but it seems they are stored on the registry, so I'm also trying to tackle this another way by:
2. Integrating [webpki-roots](https://github.com/rustls/webpki-roots) with a `SslConnectorBuilder`, but I do not see a way to add them as `X509` into the cert store due to the format they are stored in (`rustls` has a [specific method](https://docs.rs/rustls/latest/rustls/struct.OwnedTrustAnchor.html#method.from_subject_spki_name_constraints) for that for example)

Is there anything that may be useful in tackling these issues?