1. 1. Summary

Canonicalize POSIX paths in `evergreen/prelude_workdir.sh` before comparing the supplied Evergreen workdir with the checkout path. This accepts equivalent macOS symlink/mount paths while preserving rejection of stale or unrelated workdirs.

Adds `//evergreen:prelude_workdir_test` covering both cases.

1. 1. Operational benefit

Prevents macOS custom build hooks from failing before compilation when Evergreen reports `/data/mci` and the checkout resolves under `/Users/ec2-user/data/mci`.

1. 1. Safety

Windows behavior is unchanged, the original workdir is preserved for downstream commands, and mismatched or nonexistent paths still fail explicitly.