Some layers think they're going to be 'clever' and copy the values from
another layer, e.g. using ${LAYERSERIES_COMPAT_core}. The whole point of
this mechanism is to make it clear which releases a layer supports and
show when a layer master branch is bitrotting and is unmaintained.
Therefore add some code to avoid people doing this. I wish we didn't have
to but...
(Bitbake rev: 6709aedccbb2e7ddbb1b2e7e4893481a7b536436)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
d0ea143156