Providing a new build target --containers.
Container build targets typically need network access to
build, and do not need to be built as part of a regular build.
Container build targets are defined by: centos_pkg_dirs_containers
Container build targets can utilize the std and rt repos for
their build requirements.
Container target enables the mock flag: rpmbuild_networking
This also includes a fix where build-pkgs --installer in parallel
mode was building in serial mode instead.
Story: 2003909
Task: 27632
Change-Id: I3727a15fbdadc345a104c2af3446aee845171309
Signed-off-by: Al Bailey <Al.Bailey@windriver.com>
aa15df5887