Darwin CI seems to fail because of missing xcode installation
Summary
I get these sort of errors:
warning: Nix search path entry '/nix/var/nix/profiles/per-user/root/channels' does not exist, ignoring
/nix/store/ck1slah4x89kplmi4701nwgm152075l0-toolchain
...
Using 9374f116c489443bb61df4ff148edb9c641104dd for performance metric baseline...
xcode-select: error: no developer tools were found at '/Applications/Xcode.app', and no install could be requested (perhaps no UI is present), please install manually from 'developer.apple.com'.
Expected behavior
This happened on this CI job: https://gitlab.haskell.org/ghc/ghc/-/jobs/1680663
Seems like a missconfiguration issue?