ftp://ftp.ntnu.no/old/pub/X11/R5contrib/xscreensaver-1.17.tar.gz

[xscreensaver] / utils / README

This directory contains various utilities that are used both by the 
screensaver driver and by the demo programs; for example, a portable
implementation of usleep(), and code for manipulating color maps.

If you have compilation problems, check the parameters in ../config.h.