build checks.x86_64-linux.shell

Reproduce this run
  1. 0.10 s $ /nix/store/9ypz3flqsrl5xl495mm8h645gadjsxi1-coreutils-9.11/bin/timeout --kill-after=15s 7200s /nix/store/23zk8sgzamrbmj1fday15szf7f2279s8-nix-2.34.7/bin/nix --extra-experimental-features nix-command --extra-experimental-features flakes --log-format internal-json build --no-link --print-out-paths git+https://github.com/NorfairKing/sydtest?ref=mutation-control-group&rev=8aca3834dcb815e77aa840eae2e985a585994d8a#checks.x86_64-linux.shell --print-build-logs
  2. 0.13 s warning: ignoring untrusted flake configuration setting 'extra-substituters'.
  3. 0.13 s Pass '--accept-flake-config' to trust it
  4. 0.13 s warning: ignoring untrusted flake configuration setting 'extra-trusted-public-keys'.
  5. 0.13 s Pass '--accept-flake-config' to trust it
  6. 3.02 s
  7. 6.63 s /nix/store/mkazwlf30sry4628a3a3y151ljk6ia2g-sydtest-shell
  8. 6.71 s Build succeeded.