Describe the bug

The hydra macOS jobs are failing with objc[91749]: +[__NSCFConstantString initialize] may have been in progress in another thread when fork() was called.
This seems to be non-deterministic.

Steps To Reproduce

https://hydra.nixos.org/build/252305874/nixlog/1

Expected behavior

Have it build

nix-env --version output

Additional context

Add any other context about the problem here.

Priorities

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