these 2 derivations will be built:
  /nix/store/1x9fnk0gy1l346cvpfjc9hf9gjnhmpan-libfprint-2.pc.drv
  /nix/store/cfqywvvxzm6zp9cg00i1ip72a2zlqx2b-libfprint-focaltech-1.94.9.drv