anchor.diff:  
   ARG CC=/usr/bin/gcc-5
   ARG CXX=/usr/bin/g++-5
  +ARG CFLAGS="-D_GLIBCXX_USE_CXX11_ABI=0 -fPIC -g -fno-omit-frame-pointer -O3 -pthread"
  +ARG CXXFLAGS="-D_GLIBCXX_USE_CXX11_ABI=0 -fPIC -g -fno-omit-frame-pointer -O3 -pthread"
   
   ARG FOLLY_SHA=f2a8b592861472bf47495c40519fdd778b420bc1 
   ARG WANGLE_SHA=9ed41ea931c1039d2eb80b9152577bbe714f9b71
  
positive.code:         bison \
          build-essential \
          clang-3.7 \
          clang-tidy-3.7 \
          cmake \
          curl \
          flex \
          g++-5 \
          gdc \
          git \
          gperf \
          libboost-all-dev \
          libcap-dev \
          libdouble-conversion-dev \
          libevent-dev \
          libgflags-dev \
          libgoogle-glog-dev \
          libgtest-dev \
          libjemalloc-dev \
          libkrb5-dev \
          liblz4-dev \
  
negative.code:     echo "  cxx    = /usr/bin/clang++-3.7"  >> /root/.buckconfig && \
      echo "  cxxpp  = /usr/bin/clang++-3.7"  >> /root/.buckconfig && \
      echo "  ld     = /usr/bin/clang++-3.7"  >> /root/.buckconfig && \
      echo "  cxxflags = -std=c++14 ${CXXFLAGS} -Wextra" >> /root/.buckconfig
  
  # Right now, if buckd is enabled in virtualbox one of two things will happen:
  #  - If the project is mounted on a virtualbox shared folders dir,
  #    mmap will not work, and https://github.com/facebook/buck/blob/master/src/com/facebook/buck/cxx/ObjectFileScrubbers.java
  