Follow WORKDIR -> UNPACKDIR transition

[ejoerns]

This adapts to the oe-core rework to enforce a separate directory for unpacking local sources (UNPACKDIR) instead of polluting WORKDIR directly.

Follows the preliminary guidelines from:
https://lists.openembedded.org/g/openembedded-architecture/message/2007

For this, we need to break compatibility with all releases before master.

[troth]

Testing your patches for this and I see the following WARNING:

WARNING: rauc-conf-1.0-r0 do_unpack: rauc-conf: the directory ${WORKDIR}/${BP} (/home/troth/work/judo/judo-main/build/tmp/work/armv7at2hf-neon-trimble-linux-gnueabi/rauc-conf/1.0/rauc-conf-1.0) pointed to by the S variable doesn't exist - please set S within the recipe to point to where the source has been unpacked to

Adding the following after SRC_URI should quell the warning:

S = "${WORKDIR}/sources"
UNPACKDIR = "${S}"

[ejoerns]

@troth Indeed, I get the same error when building rauc-conf. No idea why I missed this, thanks for the hint!

I also wasn't fully aware yet that setting S became mandatory with the recent oe-core changes.

[ejoerns]

Should have read this paragraph :)

Previously, S was always created but after the recent changes it is
not. This means the check in do_unpack_qa triggers where S is not
created by a recipe where as it did not before. This can mean adding a
S definition to a recipe that only uses file:// SRC_URI entries.