Switch to prebuilt exe zipapp maker

[rickeylev]

This is a tracking issue for the various work needed to switch to a prebuilt version of the rust-based exe-zip maker tool.

• Figure out answer to how to handle non-prebuilt platforms
• Create dev-only toolchain to build from source
• Update release workflows to build stataic binary for: {arm,x86} x {linux,windows,mac}
• Upload artifacts to release page
• Add a --build_tools_from=<source|prebuilt> flag (name TBD) to control if the tool comes from source or from a prebuilt URL
• Update release process to refer to release URLs
• Go back and make the above steps required
• Go back and enable the flag by default

Open questions

If from-source is used as the fallback, then we need to add workspace support (currently we stub out rules_rust in workspace mode)

[aignas]

For non x86 or arm platforms what should we do? I think if it is free to build for toolchain target platforms, I'd go for that instead. That can be one of the to do items before making the flag default.

[rickeylev]

I have a few ideas, but wasn't sure which we should do.

First option is to to have a from source tool chain as the last tool chain. I didn't like this because it means we have to have a non-dev dependency on rules_rust for an edge case / unsupported platforms. Jeremy suggested a variation where we split out a separate module whose only purpose is to register the tool chain (rules_python uses it as a dev dependency; users can depend on it if they need it).

Second option is to just always have the from source tool chain as the last one. The easiest option.

Third option would be to keep the python impl as the fall back. I don't like this one.

Fourth option is to cross build, assuming we can.

On a side note, building these for release will eventually be annoying because we don't have RBE, so it'll be slower and a different environment than our tests. Which I hope doesn't cause any issues.

[rickeylev]

Another complication of from source builds: it expands support to bazel version and bzlmod/workspace mode. Right now we stub out rules_rust for workspace mode (I can't remember if its because of laziness or rules_rust doesn't support workspace anymore)

[aignas]

Another for the zip maker is to have a separate bazel module for the toolchain implementation and allow users to just include the module itself and register a toolchain that will force the maker to be built from source.

1. In rules_python we use pre-built
2. We fail if we don't find it
3. The user can add the bazel dep to the zip builder if needed. They can configure the rust toolchain.

[aignas]

Links:

• https://github.com/uber/hermetic_cc_toolchain
• some notes: https://aethermesh.dev/proposals/008-rust-in-bazel/
• get inspired by https://github.com/hermeticbuild/hermetic-launcher