anchor.diff:      && apt-get purge -y ${BUILD_PACKAGES} \
       && apt-get autoremove -y \
       && apt-get clean \
  -    && rm -rf /var/lib/apt/lists/*
  +    && rm -rf /var/lib/apt/lists/* pg_repack-${PG_REPACK_COMMIT}
   
   ENV PATH=$PATH:/usr/lib/postgresql/${PGVERSION}/bin
   
  
positive.code:     # forbid creation of a main cluster when package is installed
      && sed -ri 's/#(create_main_cluster) .*$/\1 = false/' /etc/postgresql-common/createcluster.conf \
  
      && for version in ${PGOLDVERSIONS} ${PGVERSION}; do \
              # next two lines are necessary to install exact versions of libpq5 and libpq-dev (to compile extensions)
              sed -i "s/ main.*$/ main $version/g" /etc/apt/sources.list.d/pgdg.list \
  
negative.code:                         libpq5=$version* libpq-dev=$version* postgresql-server-dev-${version} \
  
              # install 3rd party extensions
              && for extension in quantile trimmed_aggregates; do \
                  pgxn install $extension; \
              done \
  
              # Install pg_repack
              && make -C pg_repack-${PG_REPACK_COMMIT} clean install \
  
              # Install pg_rewind on 9.3 and 9.4
              && if [ "$version" = "9.3" ] || [ "$version" = "9.4" ]; then \
  