As Linux kernel, edk2, virtiofd, SPDK are all build from source, we
need to find a way to reduce the number of source code build.
To address this issue, this commit adds a stage that touching a
".built" file to each repo of the source code after a successfully
build. By checking if the ".built" file exists, we can determine
if there is already an old build. Since the source code repo will
be removed and cloned again when we bump the repo hash, the CI will
rebuild the repo.
Signed-off-by: Henry Wang <Henry.Wang@arm.com>
0fa71ddf7e