Compiling engine_cffi v0.0.1 (/Users/travis/build/pantsbuild/pants/src/rust/engine/engine_cffi)
error[E0463]: can't find crate for `cbindgen`
  --> engine_cffi/build.rs:28:5
   |
28 | use cbindgen;
   |     ^^^^^^^^ can't find crate
error: aborting due to previous error