Liboop is a low-level event loop management library for POSIX-based
operating systems. It supports the development of modular, multiplexed
applications which may respond to events from several sources.

It replaces the "select() loop" and allows the registration of event
handlers for file and network I/O, timers and signals. Since processes
use these mechanisms for almost all external communication, liboop can
be used as the basis for almost any application.

adns is optional dependency. When adns is installed, the script will
build a liboop adns version. No additinal commands are needed.
Configure will catch it automatically.
