message: install m4 as a dependency for oss build
  Summary: as in title.
diff: @@ -114,6 +114,7 @@ function install_dependencies_linux() {
  sudo apt-get install \
  g++ \
  cmake \
  + m4 \
  libboost-all-dev \
  libevent-dev \
  libdouble-conversion-dev \
  @@ -136,6 +137,7 @@ function install_dependencies_mac() {
  # install the default dependencies from homebrew
  brew install \
  cmake \
  + m4 \
  boost \
  double-conversion \
  gflags \
  