Unlike autotools this one doesn't installs headers.
Why may we need k3b headers in system? Is there something linking against it?
If so, I'll add install statements for them...

Also it doesn't installs k3bsetup2 by default because mostly every
modern linux have sane permissions to allow user to burn cd's whithout
such hacky crap.

+musepack is disabled due to k3b doesn't builds against recent
versions (tested with 465)