Well, initially the freetype-gl project was a bunch of files to be embedded in any project that would need to display text.
This of course requires to include the files in your project but then you do not have a third-party dependencies.
The project has grown a little bit since then and having an option to build it as a library might be useful.
Especially if you write the FindFreetype-gl.cmake macro.
And a pull request on github would be great.
Nicolas