Beanpole, thanks for all the efforts!
I just realized last night that by default, in PCBSD's KDE, there's a plasma widget called "Synergy" that acts as a GUI front-end to synergy-plus.
So for anyone else is reading this, if you run the default KDE desktop, you already have a GUI front-end for synergy-plus!
http://kde-look.org/content/show.php?content=106711