anchor.diff:  COPY ./.cicd/helpers/clang.make /tmp/clang.cmake
   # build llvm
   RUN git clone --depth 1 --single-branch --branch release_40 https://github.com/llvm-mirror/llvm.git llvm && \
  -    source /opt/rh/devtoolset-8/enable && \
  -    source /opt/rh/rh-python36/enable && \
       cd llvm && \
       mkdir build && \
       cd build && \
       cmake -G 'Unix Makefiles' -DLLVM_TARGETS_TO_BUILD=host -DLLVM_BUILD_TOOLS=false -DLLVM_ENABLE_RTTI=1 -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local -DCMAKE_TOOLCHAIN_FILE='/tmp/clang.cmake' .. && \
       make -j$(nproc) && \
       make install && \
  -    cd /
  +    cd / && \
  +    rm -rf /llvm
   # build boost
   RUN curl -LO https://dl.bintray.com/boostorg/release/1.70.0/source/boost_1_70_0.tar.bz2 && \
  -    source /opt/rh/devtoolset-8/enable && \
  -    source /opt/rh/rh-python36/enable && \
       tar -xjf boost_1_70_0.tar.bz2 && \
       cd boost_1_70_0 && \
       ./bootstrap.sh --with-toolset=clang --prefix=/usr/local && \
       ./b2 toolset=clang cxxflags='-stdlib=libc++ -D__STRICT_ANSI__ -nostdinc++ -I/usr/local/include/c++/v1' linkflags='-stdlib=libc++' link=static threading=multi --with-iostreams --with-date_time --with-filesystem --with-system --with-program_options --with-chrono --with-test -q -j$(nproc) install && \
  -    cd .. && \
  -    rm -f boost_1_70_0.tar.bz2    
  +    cd / && \
  +    rm -rf boost_1_70_0.tar.bz2 /boost_1_70_0
   # build mongodb
   RUN curl -LO https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-amazon-3.6.3.tgz && \
       tar -xzf mongodb-linux-x86_64-amazon-3.6.3.tgz && \
  -    rm -f mongodb-linux-x86_64-amazon-3.6.3.tgz
  +    rm -rf mongodb-linux-x86_64-amazon-3.6.3.tgz
   # build mongodb c driver
   RUN curl -LO https://github.com/mongodb/mongo-c-driver/releases/download/1.13.0/mongo-c-driver-1.13.0.tar.gz && \
  -    source /opt/rh/devtoolset-8/enable && \
  -    source /opt/rh/rh-python36/enable && \
       tar -xzf mongo-c-driver-1.13.0.tar.gz && \
       cd mongo-c-driver-1.13.0 && \
       mkdir -p build && \
  
positive.code:     make -j$(nproc) && \
      make install && \
      cd / && \
      rm -rf mongo-c-driver-1.13.0.tar.gz
  # build mongodb cxx driver
  RUN curl -L https://github.com/mongodb/mongo-cxx-driver/archive/r3.4.0.tar.gz -o mongo-cxx-driver-r3.4.0.tar.gz && \
      source /opt/rh/devtoolset-8/enable && \
      source /opt/rh/rh-python36/enable && \
      tar -xzf mongo-cxx-driver-r3.4.0.tar.gz && \
      cd mongo-cxx-driver-r3.4.0 && \
      sed -i 's/\"maxAwaitTimeMS\", ount/\"maxAwaitTimeMS\", static_cast<int64_t>(count)/' src/mongocxx/options/change_stream.cpp && \
      sed -i 's/add_subdirectory(test)//' src/mongocxx/CMakeLists.txt src/bsoncxx/CMakeLists.txt && \
      cd build && \
      cmake -DBUILD_SHARED_LIBS=OFF -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local -DCMAKE_TOOLCHAIN_FILE='/tmp/clang.cmake' .. && \
      make -j$(nproc) && \
      make install && \
      cd / && \
      rm -f mongo-cxx-driver-r3.4.0.tar.gz
  # add mongodb to path
  ENV PATH=${PATH}:/mongodb-linux-x86_64-amazon-3.6.3/bin
  # install ccache
  
negative.code:     make -j$(nproc) && \
      make install && \
      cd .. && \
      rm -rf cmake-3.13.2.tar.gz /cmake-3.13.2
  COPY ./.cicd/helpers/clang-devtoolset8-support.patch /tmp/clang-devtoolset8-support.patch
  # build clang8
  RUN git clone --single-branch --branch release_80 https://git.llvm.org/git/llvm.git clang8 && cd clang8 && git checkout 18e41dc && \
  