these 2 derivations will be built:
  /nix/store/m8drmxixkj3dp0ann5gny9ij6lf8jsbf-source.drv
  /nix/store/2idvz2yg0m83d2y75jkcp9xmxvhjskn7-git-xet-0.2.1.drv
warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy