For Arch Linux exists an AUR package which you can install with one of the AUR-Helpers (e.g. aurman):
aurman -S witfocus
In order to run witfocus you require the following programs to be installed: bash vim gawk coreutils.
To build it from the source you will need the autotools (aka autoconf and automake).
Download the source, extract it and run the following commands:
autoreconf --install
./configure
make
sudo make install