these 5 derivations will be built:
  /nix/store/priyi8pvwlkrsqww824xp42xbmmb4j1x-source.drv
  /nix/store/lg9ki9dyjrwsxifvzk6dsq06pqqkz8sj-lean-ctx-3.12.3-vendor-staging.drv
  /nix/store/y1pmmmsn3sphvk350bin6q2kay7nvn4d-lean-ctx-3.12.3-vendor.drv
  /nix/store/xdykwry2mqn5i0cx8w02iv0d1i0x1axm-lean-ctx-3.12.3.drv
  /nix/store/5gyv20p41ag74pk9vgkqvs26f1rjwcpv-check-lean-ctx.drv