[krbdev.mit.edu #6561] No option to only build client and libs

[Greg Hudson via RT]

If this build system support would make life easier for Gentoo's package
system, that's a valid use case.  I don't think other OS packaging
systems would make use of the functionality (they would still use "make
install" and then use file lists to split up the binary packages), but
even one distribution's needs are relevant.

So, no promises, but if I have time I will see how complicated this
really is.