cxx zig toolchain doesn't work on macOS

[jazzdan]

I understand that the zig toolchain is experimental but I figured I'd report this here for others.

The zig toolchain calls ln with flags that don't exist on macOS. Building a hello world C file results in this error:

$ buck2 build //:hello
Action failed: toolchains//:zig (cp_compiler)
Local command returned non-zero exit code 1
Reproduce locally: `env -- "BUCK_SCRATCH_PATH=buck-out/v2/tmp/toolchains/213ed1b7ab869379/__zig__/cp_compiler" ln -srf b ...<omitted>... e__/zig-archive/zig-macos-aarch64-0.9.1//zig buck-out/v2/gen/toolchains/213ed1b7ab869379/__zig__/zig (run `buck2 log what-failed` to get the full command)`
stdout:
stderr:
ln: illegal option -- r
usage: ln [-s [-F] | -L | -P] [-f | -i] [-hnv] source_file [target_file]
       ln [-s [-F] | -L | -P] [-f | -i] [-hnv] source_file ... target_dir
       link source_file target_file
Build ID: c02e1d44-46bf-4c97-b33c-17e8b7e65c7f
Network: Up: 0B  Down: 37MiB
Jobs completed: 20. Time elapsed: 6.3s.
Cache hits: 0%. Commands: 2 (cached: 0, remote: 0, local: 2)
BUILD FAILED
Failed to build 'toolchains//:zig (prelude//platforms:default#213ed1b7ab869379)'

$ sw_vers
ProductName:		macOS
ProductVersion:		13.6
BuildVersion:		22G120

Repro steps

1. git clone git@github.com:jazzdan/buck2_zig_toolchain_macos_bug.git
2. cd buck2_zig_toolchain_macos_bug
3. buck2 build //:hello

[jazzdan]

@aherrmann you inspired me to try this toolchain after our talk in Reykjavik. :)