This change to stage 4 of the SDK bootstrap process will keep a
snapshot of coreos-overlay in the SDK tarball. This snapshot can be
used in future SDK bootstraps' stage1 to ensure a clean stage 1 output
without any package updates.
Signed-off-by: Thilo Fromm <thilo@kinvolk.io>
Before, we were relying on the toolchains job to build and upload
packages that were part of the SDK. With this change, all packages that
should be part of the SDK are built and uploaded by the SDK job. The
toolchains job only builds toolchain packages specific for the release.
This change includes several adjustments done to both the SDK and the
toolchains jobs to make this work:
* Make the SDK job build all cross toolchains, including Rust
* Stop building Rust in the toolchains job and use the one in the SDK
instead.
* In toolchain_util.sh: detect when the symlink folder for crossdev
packages is missing and run crossdev to create it during
update_chroot setup.
* Make it possible to build the SDK starting from stage 4 instead of
stage 1, to make the SDK building faster for PR branches / nightlies
(full build should still be done for releases / weeklies).
