[kylelanman]

Have you previously used Homebrew (e.g. brew install [package]) or installed gcc in some other manner?

One of the students on our team was able to install the 2016 tool chain and get it working with out any problems. When I tried I ran into the same problem you are having. I use Homebrew and the thing that seems suspicious is that the project is referencing some Homebrew include paths. I spent a couple of hours messing around with it and then gave up.