Draft: redhat/kernel.spec: _buildvars_variant
This introduces a new macro that allows to override variant/config to use for standalone tools/tests build.
In SPEC, we support building standalone tools and selftests. Main user are CKI pipelines, which run a native build. Over time however, selftests introduced also kmods, so picking a correct config now matters as well.
This patch allows CKI (or other users) to pick a variant when doing standalone tools/tests build. Nothing is changing for builds that include kernel build.
Signed-off-by: Jan Stancek jstancek@redhat.com