Used http://wcp.sdf-eu.org/software/sclf-20150207T213551.tbz (sha256
a231aeecdb9e87c72642292a1e083fffb33e69ec1d34e667326c6c35b8bcc794).
There's no upstream repository nor a release since 2015, so importing
seems to make a lot of sense.
Since we can't subtree making any depot-related changes in a separate CL
to make them more discoverable -- this is only the source import.
Change-Id: Ia51a7f4029dba3abd1eee4eeebcf99aca5c5ba4c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3376
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>