If you are a contributor and plan to build and run tests, install the following as well:
```sh
- $ # libgflags-dev is only required if building with make (deprecated)
- $ [sudo] apt-get install libgflags-dev
$ # clang and LLVM C++ lib is only required for sanitizer builds
$ [sudo] apt-get install clang-5.0 libc++-dev
```
If you plan to build using CMake, follow the instructions from https://cmake.org/download/
-If you are a contributor and plan to build and run tests, install the following as well:
-```sh
- $ # gflags is only required if building with make (deprecated)
- $ brew install gflags
-```
-
*Tip*: when building,
you *may* want to explicitly set the `LIBTOOL` and `LIBTOOLIZE`
environment variables when running `make` to ensure the version