• Xlib headers
• ttf-font-awesome - Provides pretty icons for each module
• mpc - Prints song artist & title if mpd is installed and configured
• pulsemixer - Prints volume levels
• freetype2 - Ensures that font-awesome glyphs display correctly.

cd into the slstatus folder, then run sudo make clean install. If using xinit, ensure that a line containing slstatus & is added to .xinitrc before exec <WM>.