ntk is a fast and lightweight GUI toolkit for the Non-DAW application
suite. It is a build requirement of Non, and is distributed along with
Non source code. It is packaged separately for SlackBuilds.org because
other software (such as Qtractor) can use it, plus in order for Non-* to 
build, ntk must be installed first. 

So, install this first, and then build and install Non.

The only official download is available as a git repository. In order
to standardise this SlackBuild, a snapshot of the git repository as of
23/09/2014 (commit e230929a579d7f91df7d34a4c0a324fb8dd5fa4a) has been
posted to http://slackermedia.info, which this SlackBuild uses.
