GRASS (Geographic Resources Analysis Support System) is a free Geographic
Information System (GIS) used for geospatial data management and
analysis, image processing, graphics/maps production, spatial modeling,
and visualization.  GRASS is an official project of the Open Source
Geospatial Foundation.

The following optional dependencies may be enabled:
  blas lapack geos ffmpeg mysql postgresql sqlite

The options you require must be specified by setting the variable ENABLE
before running grass.SlackBuild, for example

  ENABLE="sqlite,ffmpeg" ./grass.SlackBuild

If you need to make grass libraries available on the system, do this:
echo /opt/grass/lib >> /etc/ld.so.conf && ldconfig