these 4 derivations will be built:
  /nix/store/igp0nspx032jv65l15v2ll7iwi0hvw0m-Cargo.toml.drv
  /nix/store/9h8wki3whadn5hn59sjr7ial42rjis8r-source.drv
  /nix/store/1ipc2i2v45l6zscvcn9061x16fl08n7m-harmonia-deps-3.1.0.drv
  /nix/store/vb0qs5liqz093jibhyspisqmm8w43p20-harmonia-llvm-cov-3.1.0.drv
error: Cannot build '/nix/store/vb0qs5liqz093jibhyspisqmm8w43p20-harmonia-llvm-cov-3.1.0.drv'.
       Reason: builder failed with exit code 101.
       Output paths:
         /nix/store/404r4f3x2g6k6nndw9p4idrrgwnfinph-harmonia-llvm-cov-3.1.0
       Last 1 log lines:
       > tribuchet: building on jamie
       For full logs, run:
         nix log /nix/store/vb0qs5liqz093jibhyspisqmm8w43p20-harmonia-llvm-cov-3.1.0.drv