anchor.diff:      sha256sum --check bazel.sha256 && \
       apt-get install -y \
           ./bazel.deb \
  +        bash-completion \
           build-essential \
           git \
           libfl2 \
           ocaml-nox \
           ocamlbuild \
  -        python3 \
  +        python-dev \
  +        python2.7-dev \
  +        python3-dev \
           vim \
           && \
       rm bazel.deb bazel.sha256 && \
  
positive.code: 
  # Use fixed snapshot of Debian to create a deterministic environment.
  # Snapshot tags can be found at https://hub.docker.com/r/debian/snapshot/tags
  ARG debian_snapshot=buster-20190708
  
  # Start with a temporary image just for building the toolchain.
  FROM debian/snapshot:${debian_snapshot} as toolchain
  
negative.code: FROM debian/snapshot:${debian_snapshot}
  
  # Use a fixed version of Bazel.
  ARG bazel_version=1.2.1
  ARG bazel_sha=4bbb2718d451db5922223fda3aed3810c4ca50f431481e86a7fec4c585f18b1f
  ARG bazel_url=https://storage.googleapis.com/bazel-apt/pool/jdk1.8/b/bazel/bazel_${bazel_version}_amd64.deb
  
  # Install development tools
  