anchor.diff:  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   # See the License for the specific language governing permissions and
   # limitations under the License.
  +
  +# Copy some commonly linked library versions from xenial for backwards
  +# compatibility with older builds.
  +FROM ubuntu:16.04 as xenial
  +ENV DEBIAN_FRONTEND noninteractive
  +RUN apt-get update && \
  +    apt-get install -y \
  +      libcurl3-gnutls \
  +      libffi6 \
  +      libnettle6 \
  +      libssl1.0.0
  +
   FROM ubuntu:20.04
   
   RUN mkdir /data
  
positive.code:         libcurl4-openssl-dev \
          libffi-dev \
          libgdbm-dev \
          liblzma-dev \
          libncurses5-dev \
          libnss3-dev \
          libreadline-dev \
          libsqlite3-dev \
          libssl-dev \
          locales \
          lsb-release \
          net-tools \
  
negative.code:         wget \
          zip \
          zlib1g-dev
  
  COPY --from=xenial \
      /lib/x86_64-linux-gnu/libcrypto.so.1.0.0 \
      /lib/x86_64-linux-gnu/libssl.so.1.0.0 \
      /lib/x86_64-linux-gnu/
  COPY --from=xenial \
      /usr/lib/x86_64-linux-gnu/libcurl-gnutls.so.* \
      /usr/lib/x86_64-linux-gnu/libffi.so.6.* \
      /usr/lib/x86_64-linux-gnu/libnettle.so.* \
      /usr/lib/x86_64-linux-gnu/
  
  # Install patchelf.
  RUN curl -sS https://releases.nixos.org/patchelf/patchelf-0.9/patchelf-0.9.tar.bz2 | tar -C /tmp -xj && \
  