[OE-core] Automatic -dbg FILES generation

[Richard Purdie]

I don't think I'm alone in being a bit frustrated with the effort
needed to get FILES_${PN}-dbg correct. I've just posted a patch to oe
-core which automates this and means we can drop 99% of the cases where
we set this variable.

I'm giving a heads up here since this is an architectural change to the
way the system works and wanted people to be aware of it. I'm hoping it
will be welcomed and not too controversial.

Setting FILES_${PN}-dbg doesn't harm anything, it just becomes
unnecessary in most cases.

Cheers,

Richard