1.) prefix all functions in the library with devstat_ (compatability
functions are available for all functions that were chaned in an
incompatible way, but are deprecated).
2.) Add a pointer to a kvm_t as the first argument to functions that
used to get their information via sysctl; they behave the same
as before when NULL is passed as this argument, otherwise, the
information is obtained via libkvm using the supplied handle.
3.) Add a new function, devstat_compute_statistics(), that is intended
to replace the old compute_stats() function. It offers more
statistics data, and has a more flexible interface.
libdevstat does now require libkvm; a library depedency is added, so
that libkvm only needs to be explicitely specified for statically linked
programs.
The library major version number is bumped.
Submitted by: Sergey A. Osokin <osa@freebsd.org.ru>, ken (3)
Reviewed by: ken
