systemd_unitdir indicates the arch independent
files which are basically scripts and unit files
and systemd wants then to be in /lib always even
when base_libdir is /lib64, hence we have to reflect
that and not use base_libdir to define it. Otherwise
on architectures where base_libdir is lib64 e.g. ppc64
or multilibbed x86_64 this wont work
Signed-off-by: Khem Raj <raj.khem@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>