Zig tracking issue

This was copied over from #453, which is pretty stale, but it's a starting point.

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Overall we're very happy with using Zig. We've been following the latest major release when possible.

Some pain points, with some related issues linked:

• Compilation speed We use almost exclusively Debug and ReleaseSafe. For example, changing one line and re-building one test in Debug takes somewhere around 20 seconds right now which interrupts flow. Incremental seems a long way out still, but using self-hosted backends for our Debug builds on x86-64-linux and aarch64-macos would be great. https://github.com/ziglang/zig/issues/22257 https://github.com/ziglang/zig/issues/21172

• Implicit pass by reference This can be a bit of footgun as-is. As I understand, this is already on its way out of the language, we just don't know when. It has been a source of confusion. https://github.com/ziglang/zig/issues/5973#issuecomment-2380332493

Some newer features we're particularly happy with:

• Build system and package manager We've been getting a lot of mileage out of it, and are maintaining a few (hopefully reusable) packages:
  • lmdb-zig
  • rocksdb-zig
  • base58-zig
  • zstd.zig

Things that aren't priorities for us:

• Removing LLVM from the compiler as a whole. We'll still want highly optimised builds, and we'll still want Clang for some important dependencies.