Go to the download section of ddccontrol project's page and download the latest ddccontrol and ddccontrol-db source tarballs.

Then unpack these two archives with:

# tar xvfz ddccontrol-X.Y.tar.gz
# tar xvfz ddccontrol-db-YYYYMMDD.tar.gz

You should now have two directories, ddccontrol and ddccontrol-db.