osgEarth is a C++ terrain rendering toolkit. Just create a simple XML file,
point it at your imagery, elevation, and vector data, load it into your favorite
OpenSceneGraph application, and go!

osgEarth supports all kinds of data and comes with lots of examples to help you
get up and running quickly and easily.

Some optional requirements are recommended for enhanced functionality
and/or performance. They include:
    osgQt, poco, protobuf, rocksdb

For all but osgQt, they will be used if detected when osgEarth is built.

In the case of osgQt, the version of Qt that it was built with is relevant.
If osgQt was built with Qt5, the environment variable OSGQT=5 must be set when
running the osgEarth SlackBuild i.e.
    OSGQT=5 sh osgEarth.SlackBuild
In this case, the qt5 package is also an additional build requirement.

If osgQt was built with Qt4 (the standard for Slackware 14.2), set OSGQT=4 i.e.
    OSGQT=4 sh osgEarth.SlackBuild

If OSGQT is not set, osgQt support will not be included.