[oe] multiple DISTRO's in tmp

[Frans Meulenbroeks]

I bumped upon the following issue.

Normally I use angstrom as distro, but this time I needed a small
image to be used in an initramfs.
In order to achieve that I changed DISTRO in my local.conf to minimal
(tried minimal-uclibc first, but that would complain before generating
packages, probably due to a mismatch between my target (powerpc) and
uclibc (I refrained from sidetracking to dig into it)).

However, when trying to build minimal, it immediately complained about
DISTRO_PR (minimal does not have DISTRO_PR, which you may find a bug,
but anyway that is what exists now).
I had to put it in a new tmp dir.

However, I was wondering: wouldn't it be nice to allow multiple
distro's in one tmp dir (so that e.g. if they share the same version
of a recipe (like m4-native or os), this does not need to be
recompiled?

If this is considered to be a good plan what would be the best way to
achieve this?

Frans