anchor.diff:  
   # Add tour packages under their old import paths (so old snippets still work)
   RUN mkdir -p $GOPATH/src/code.google.com/p/go-tour && \
  -	cp -R $GOPATH/src/golang.org/x/tour/* $GOPATH/src/code.google.com/p/go-tour/ && \
  -	sed -i 's_// import_// public import_' $(find $GOPATH/src/code.google.com/p/go-tour/ -name *.go) && \
  -	go install \
  -		code.google.com/p/go-tour/pic \
  -		code.google.com/p/go-tour/reader \
  -		code.google.com/p/go-tour/tree \
  -		code.google.com/p/go-tour/wc
  +    cp -R $GOPATH/src/golang.org/x/tour/* $GOPATH/src/code.google.com/p/go-tour/ && \
  +    sed -i 's_// import_// public import_' $(find $GOPATH/src/code.google.com/p/go-tour/ -name *.go) && \
  +    go install \
  +    code.google.com/p/go-tour/pic \
  +    code.google.com/p/go-tour/reader \
  +    code.google.com/p/go-tour/tree \
  +    code.google.com/p/go-tour/wc
   
   # Add and compile sandbox daemon
   COPY . /go/src/sandbox/
  
positive.code: 
  RUN set -x && buildDeps='curl ca-certificates gcc patch libc6-dev'; \
      apt-get update && apt-get install -y $buildDeps --no-install-recommends && rm -rf /var/lib/apt/lists/* && \
  # Get the Go binary.
      curl -sSL https://storage.googleapis.com/golang/go$GO_VERSION.linux-amd64.tar.gz -o /tmp/go.tar.gz && \
      curl -sSL https://storage.googleapis.com/golang/go$GO_VERSION.linux-amd64.tar.gz.sha256 -o /tmp/go.tar.gz.sha256 && \
      echo "$(cat /tmp/go.tar.gz.sha256)  /tmp/go.tar.gz" | sha256sum -c - && \
      tar -C /usr/local/ -vxzf /tmp/go.tar.gz && \
      rm /tmp/go.tar.gz /tmp/go.tar.gz.sha256 && \
  
  # Make a copy for GOROOT_BOOTSTRAP, because we rebuild the toolchain and make.bash removes bin/go as its first step.
      cp -R /usr/local/go $GOROOT_BOOTSTRAP && \
  
  # Apply the fake time and fake filesystem patches.
      patch /usr/local/go/src/runtime/rt0_nacl_amd64p32.s /usr/local/sandbox/enable-fake-time.patch && \
      cd /usr/local/go && go run misc/nacl/mkzip.go -p syscall /usr/local/sandbox/fake_fs.lst src/syscall/fstest_nacl.go && \
  
  # Re-build the Go toolchain.
      cd /usr/local/go/src && GOOS=nacl GOARCH=amd64p32 ./make.bash --no-clean && \
  
  # Clean up.
      rm -rf $GOROOT_BOOTSTRAP && \
      apt-get purge -y --auto-remove $buildDeps
  
  
negative.code: ENV GOPATH /go
  ENV PATH /usr/local/go/bin:$GOPATH/bin:$PATH
  ENV GOROOT_BOOTSTRAP /usr/local/gobootstrap
  ENV GO_VERSION 1.9.2
  
  # Fake time
  COPY enable-fake-time.patch /usr/local/sandbox/
  