Derelict is a group of D packages which provide bindings to a number of C libraries. The bindings are dynamic, in that they load shared libraries at run time. DerelictUtil is the common code base used by each package. It provides a cross-platform mechanism for loading shared libraries, exceptions that indicate failure to load, and common declarations that are useful across multiple platforms.
For more information on how to use DerelictUtil, either as the user of a dynamic binding based on DerelictUtil or as the implementor of a custom binding, see the DerelictUtil wiki.