Support for Fortanix SGX target (x86_64-fortanix-unknown-sgx)

[sburton84]

Support for Fortanix SGX target (x86_64-fortanix-unknown-sgx)

[jsha]

I'd like to avoid magic numbers if we can.

It seems like there is arguably room for another extension point. We have Resolver, which turns names into IP addresses. We have TlsConnector, which turns a dialed TCP connection into a TLS stream. We could add Dialer, which creates a TCP (or other socket) connection. For the Fortanix use case described above this would require a fake Resolver that doesn't actually do name resolution, but that's doable.

[algesten]

Wonder if we could solve this without changing the API with an internal hack?

We could make up a magic number IPv6 SocketAddr, which when returned from a resolver, triggers the behavior of passing the hostname straight to TcpStream::connect.