My shell version of this ports system has some nifty features, like support for git repositories. There's tons of software you have to compile yourself from git. This manages those programs, the compilation, installation and deinstallation.
sudo install -o $USER -d /usr/sports
git clone https://github.com/hboetes/sports.git /usr/sports
cd /usr/sports/core/pkgutils/
./bootstrap
cd /usr/sports/opt/emacs
pkgmk -i
Just look at a few other ports. It's pretty simple actually.