[04/05] Embedded with systemd: systemd and kernel upgrades

[Robert <debembedded@gmail.com>]

This was recently posted on #systemd-devel:

"To make this clear, we expect that systemd and kernels are updated in
lockstep. We explicitly do not support really old kernels with really
new systemd. So far we had the focus to support up to 2y old kernels
(which means 3.4 right now), but even that should be taken with a grain
of salt, as we already made clear that soon after kdbus is merged into
the kernel we'll probably make a hard requirement on it from the systemd
side."

This is a very onerous requirement in the embedded world. There are many
embedded platforms sold today that only have 2.6.X BSPs. While I agree
that the BSP from vendors should be better (and it is getting better
thanks to devicetree), it seems that we are doomed to run ancient
userspace to match our ancient kernels.

This change will probably hit me the hardest and for me it really cuts
into what linux means. It used to be that I could run the same userspace
on my tiny embedded device, my desktop or on the server --- the only
difference being the kernel.

It seems like the only solution here is to abandon debian and fall back
to OpenEmbedded or buildroot.