Improve support for ACLs in coreutils (ls & chmod) following the Solaris way

[Ondrej Valousek <ondrej.valousek.xm@renesas.com>]

Hi,

As per our conversation with Bruno I was thinking if it would make a sense to extend support of ACLs in gnulib/coreutils, mainly covering "ls" (1st stage) and "chmod" (2nd stage)  with the goal to have the ACLs better understandable for end users.  

For "ls" we would:
- Introduce a new flag "-V" that would work like "-l" but also append text interpretation of ACLs as in Solaris, i.e.:
# ls -V 
total 7
-rw-r--r--+  1 root     root           5 Jan  4 09:11 acl
            user:ondrej:rwx-----------:-------:allow
                 owner@:rw-p--aARWcCos:-------:allow
                 group@:r-----a-R-c--s:-------:allow
              everyone@:r-----a-R-c--s:-------:allow

For "chmod" we would add new option "A" that would allow modify ACEs like in Solaris:
# chmod A+user:marks:rw- file.1

Technical implementation:
- I'd like to support NFSv4 ACLs, but since we have no library for it, then we would need to provide some parsing code for it and stick in Gnulib - we have something in "file-has-acl.c" already and it would be a good starting point.
- file_has_acl() function would need to be modified slightly to return 2 in case NFSv4 acls were found (this is backward compatible).

For Posix acls we would use the existing libacl.

Is this something I would find support in both coreutils and Gnulib?
Thanks

Ondrej