anchor.diff:  WORKDIR /tmp
   ADD https://github.com/protocolbuffers/protobuf/releases/download/v${PROTOBUF_VERSION}/protoc-${PROTOBUF_VERSION}-linux-x86_64.zip /tmp/
   RUN unzip /tmp/protoc-${PROTOBUF_VERSION}-linux-x86_64.zip
  -RUN cp -aR /tmp/bin/protoc /usr/bin
   
   # Install necessary protoc includes
  -RUN mkdir -p /usr/include/protobuf/google/protobuf /usr/include/protobuf/google/rpc /usr/include/protobuf/gogoproto
  +RUN mkdir -p ${OUTDIR}/usr/include/protobuf/google/protobuf
  +RUN mkdir -p ${OUTDIR}/usr/include/protobuf/google/rpc
  +RUN mkdir -p ${OUTDIR}/usr/include/protobuf/gogoproto
  +
   RUN for f in any duration descriptor empty struct timestamp wrappers; do \
  -            curl -L -o /usr/include/protobuf/google/protobuf/${f}.proto https://raw.githubusercontent.com/google/protobuf/master/src/google/protobuf/${f}.proto; \
  +            curl -L -o ${OUTDIR}/usr/include/protobuf/google/protobuf/${f}.proto https://raw.githubusercontent.com/google/protobuf/master/src/google/protobuf/${f}.proto; \
           done
   RUN for f in code error_details status http; do \
  -            curl -L -o /usr/include/protobuf/google/rpc/${f}.proto https://raw.githubusercontent.com/istio/gogo-genproto/master/googleapis/google/rpc/${f}.proto; \
  +            curl -L -o ${OUTDIR}/usr/include/protobuf/google/rpc/${f}.proto https://raw.githubusercontent.com/istio/gogo-genproto/master/googleapis/google/rpc/${f}.proto; \
           done
  -RUN curl -L -o /usr/include/protobuf/gogoproto/gogo.proto https://raw.githubusercontent.com/gogo/protobuf/master/gogoproto/gogo.proto
  +RUN curl -L -o ${OUTDIR}/usr/include/protobuf/gogoproto/gogo.proto https://raw.githubusercontent.com/gogo/protobuf/master/gogoproto/gogo.proto
   
   # Install external dependencies
   RUN GO111MODULE=on go get github.com/golang/protobuf/protoc-gen-go@${GOLANG_PROTOBUF_VERSION}
  
positive.code: FROM golang:1.12 as build_tools
  
  # Pinned versions of stuff we pull in
  ENV PROTOBUF_VERSION=3.6.1
  
negative.code: ENV GOIMPORTS_VERSION=379209517ffe
  ENV GOLANGCI_LINT_VERSION=v1.16.0
  
  ENV OUTDIR=/out
  
  # Update distro and install dependencies
  # TODO we probably don't need all this stuff...
  RUN apt-get update && apt-get install -y --no-install-recommends \
      autoconf \
      build-essential \
  