Libggi provides a fairly low level graphics API whilst libgii provides accompanying input routines.
It's advantage is that programmes linked against it can be run, without recompiling on a variety of targets, including
It works :)
Higher level graphics routines are provide by packages such as libggi2d and libggi3d.
Build from the source available from http://www.ggi-project.org. The UK mirror tends to be rather out-of-date.