libev (a high-performance event loop/model)

Libev is modelled (very loosely) after libevent and the Event perl
module, but is faster, scales better and is more correct, and also
more featureful. And also smaller. Yay.

Note: libev and libevent both have a usr/include/event.h
header file. This could have lead to compile problems if both
packages were installed at the same time, so it has been moved to
usr/include/libev/event.h. Add CPPFLAGS="-I/usr/include/libev" to
the SlackBuild if the software you're building over this needs the
libevent compatibility layer (lighttpd2 and i3 don't).