Note: There is a better way to do this described here.
If you’ve ever tried apt-get or brew to try to install gtest, you are
probably familiar with the fact that gtest is not “recommend” for global install
on your system. As an alternative, the recommendation is that you make it part
of your project. The process for making gtest part of your project, however, is
not well documented, at least for modern git projects. What follows is the
procedure I used to do so.