Rejigger Linux platform detection
This change makes some very small improvements to the Linux platform
detection logic. In particular, the existing logic did not work on my
Archlinux machine since /lib64/ld-linux-x86-64.so.2 isn't a symlink. In
that case, the detection logic should have fallen back to the slower
`ldd --version` technique, but `read_link` fails outright when its
argument isn't a symbolic link. So we tweak the logic to allow it to
fail, and if it does, we still try the `ldd --version` approach instead
of giving up completely.
I also made some cosmetic improvements to the regex matching, as well as
ensuring that the regexes are only compiled exactly once.
musl (which we already use in ruff) allows statically linked binaries on
linux. This PR switches to rustls and vendors and fixes the glibc
detection. Using static musl builds makes it easier to avoid glibc
errors in docker and we'll need it later for alpine users anyway.
An alternative is using vendored openssl.
## Summary
This PR enables the proof-of-concept resolver to backtrack by way of
using the `pubgrub-rs` crate.
Rather than using PubGrub as a _framework_ (implementing the
`DependencyProvider` trait, letting PubGrub call us), I've instead
copied over PubGrub's primary solver hook (which is only ~100 lines or
so) and modified it for our purposes (e.g., made it async).
There's a lot to improve here, but it's a start that will let us
understand PubGrub's appropriateness for this problem space. A few
observations:
- In simple cases, the resolver is slower than our current (naive)
resolver. I think it's just that the pipelining isn't as efficient as in
the naive case, where we can just stream package and version fetches
concurrently without any bottlenecks.
- A lot of the code here relates to bridging PubGrub with our own
abstractions -- so we need a `PubGrubPackage`, a `PubGrubVersion`, etc.
Mocks out the PyPI client using some checked-in fixtures. The test is
very basic, and I'm not very happy with all the ceremony around the
mocks and such, but it's an interesting experiment at least.
This PR modifies the `install-wheel-rs` (and a few other crates) to get
everything playing nicely. Specifically, CI should pass, and all these
crates now use workspace dependencies between one another.
As part of this change, I split out the wheel name parsing into its own
`wheel-filename` crate, and the compatibility tag parsing into its own
`platform-tags` crate.
