6a8abf277c
This allows to pre-select the build system, specifically avoiding confusion when kas-container is accidentally not called with --isar for an isar config. For that, build_system needs to be defined in the lop-level config file passed to kas-container. Theoretically, this also allows to combine layers which have both oe-init-build-env and isar-init-build-env scripts. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>