i believe apollo domain systems did something like this. as i recall,
if you extracted the file into a 4.2 ufs, the acl's were stored in
a junk file you could delete or ignore. if extracted into a domain
fs, it used the information in the file to assign the appropriate acls.
The acl info goes into a dummy file named something like /tmp/ACL-INFO.
Each file in the tar has its own dummy file, but they all have the same
name, so if you use standard tar to extract the tar, you end up with only
one junk file. It's a hack but it works.
I didn't bother making it work with afs acls when I did the apollo afs port.
