GParted uses GNU libparted to detect and manipulate devices and
partition tables. Several (optional) "file system" tools provide
support for file systems not included in libparted. These optional
packages will be detected at runtime and do not require a rebuild
of GParted. GParted is written in C++ and uses gtkmm for it's
Graphical User Interface (GUI).

gtkmm, which is available at slackbuilds.org, and parted, which
can be found on the second Slackware CD in extra/ or on any official 
Slackware mirror, are required to build gparted.