anchor.diff:  ARG C8O_BASE_VERSION
   
   RUN export GNUPGHOME="$(mktemp -d)" \
  -    && gpg --keyserver pgp.mit.edu --recv-keys 6A7779BB78FE368DF74B708FD4DA8FBEB64BF75F \
  +    && gpg --keyserver ha.pool.sks-keyservers.net --recv-keys 6A7779BB78FE368DF74B708FD4DA8FBEB64BF75F \
       && C8O_REVISION=`curl -sL -r 0-200 http://downloads.sourceforge.net/project/convertigo/${C8O_BASE_VERSION}/readme.txt | sed -nr "s/.*build ([0-9]+).*/\1/p"` \
       && curl -SL -o /tmp/convertigo.zip \
           http://downloads.sourceforge.net/project/convertigo/${C8O_BASE_VERSION}/convertigo-server-${C8O_BASE_VERSION}-v${C8O_REVISION}-linux${C8O_PROC}.run.zip \
  
positive.code:     /usr/share/doc
  
  # grab gosu for easy step-down from root and tini for signal handling
  RUN gpg --keyserver ha.pool.sks-keyservers.net --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4 \
    && curl -o /usr/local/bin/gosu -fSL "https://github.com/tianon/gosu/releases/download/1.7/gosu-$(dpkg --print-architecture)" \
    && curl -o /usr/local/bin/gosu.asc -fSL "https://github.com/tianon/gosu/releases/download/1.7/gosu-$(dpkg --print-architecture).asc" \
    && gpg --verify /usr/local/bin/gosu.asc \
  
negative.code:   && gpg --verify /usr/local/bin/tini.asc \
    && rm /usr/local/bin/tini.asc \
    && chmod +x /usr/local/bin/tini
    && rm -rf /tmp/* \
  
  ARG C8O_PROC
  RUN if [ "${C8O_PROC}" = "32" ]; then \
  