slackbuilds/graphics/ralcgm/README

ralcgm (view/convert CGM vector image files)

RAL-CGM is a program to translate or interpret CGM (Computer Graphics
Metafile) files, either to a different encoding (Binary, Character or
Clear Text) or to view on a terminal or to send to a plotter (PostScript
or HPGL).

It can be used as an ImageMagick or GraphicsMagick delegate to convert
from CGM format.

If you want to compile the example code:

gcc -o testcgm -I/usr/include/ralcgm \
    /usr/doc/ralcgm-3.50/examples/testcgm.c -lcgm -lm -lX11