I had the same question asking myself some time ago, and I wrote an article how you can do this.
First of all, you can run
make -DBATCH install clean
to accept default configuration for all packages (for dependencies too).
If you want to configure all dependencies you can run
You have to run
as many times as needed to configure all dependencies. This happens because while you are configuring dependencies, these dependencies may have more dependencies that need to be installed and configured.
Then you can run
make install clean
After all, in case you want to reconfigure or delete configuration you have to run:
You can also take a look at my article: