Add rustls-platform-verifier binding

[amesgen]

Closes #417

Have not yet taken a closer look at the Windows failures Now resolved, see the review comments below.

[amesgen]

This could also take an (optional) rustls_root_cert_store to use for Verifier::new_with_extra_roots; however, it doesn't exist on e.g. macOS and Windows, so one would either need a platform-conditional API or at least new error codes for these cases. WDYT?

[cpu]

There's an open issue (rustls/rustls-platform-verifier#58) on rustls-platform-verifier to add support for extra roots for the other platforms.

I think we should keep this simple and avoid implementing it in -ffi until the feature is available more broadly. There's not very much platform-conditional code in this repo and it'd be great to avoid adding more if we can.

[cpu]

Thank you! This is looking good. I had a few suggestions for documentation related fixes but the actual implementation is great 🌠

Have not yet taken a closer look at the Windows failures

I did some fiddling of my own and I believe we need crypt32.lib added to the Windows CMakeLists.txt in the target_link_libraries list.

Looking into that was worthwhile because (as mentioned in a review comment) it uncovered that I accidentally removed our test coverage for the expected Windows link libraries changing 😓

Applying this commit 575c80d fixes the Windows build in my testing. It tidies the overall list to match what I get using RUSTFLAGS=--print native-static-libs cargo build in CI while also adding crypt32.lib.

[cpu]

Thanks! The latest revisions look great. I left a comment suggesting we separate the new test but that's a minor detail.

[cpu]

Build+test (clang, 1.61.0, ubuntu-latest) Expected — Waiting for status to be reported
Build+test (gcc, 1.61.0, ubuntu-latest) Expected — Waiting for status to be reported

This is to be expected from the MSRV update. We'll admin merge and fixup the branch protection rules afterwards.

[jsha]

Generally looks great!

[cpu]

Thanks @amesgen !

[cpu]

This is to be expected from the MSRV update. We'll admin merge and fixup the branch protection rules afterwards.

I've retroactively fixed the branch protection rules for the new MSRV.