Continuing to bump source releases. hfs is the only one so far that I haven't been able to update, newer versions miss headers present in the SDK. I managed to get more of shell_cmds building. Only sudo is still missing but in later versions it may require entitlements so we probably wouldn't be able to keep it building anyway. I also made some changes to our header checks to include checking for symlinked headers, which are common in the SDK.
The Libc bump is more involved because it used to be an amalgam of three versions and I'm dropping all the old ones, which requires digging through the sources for missing headers. So far it seems viable to drop the older versions.