Make ACL headers required by default for Samba 4.0

[Andrew Bartlett]

A number of folks over time have hit the issue that Samba's POSIX ACL
support is optional - we work fine for most things without it, but
because of this you only notice it being missing much later, when you
start to really need it.

To catch this issue for potential deployments of the Samba 4.0 AD DC, I
have a trap in the provision stage that checks for ACL support on the
current file system, but it seems to me that this point is too late in
the process.

I propose that by default, we should require some form of system ACL
header to build Samba.  Then, if a user is on a system without ACL
headers or is unwilling to install them, they can specify the
--without-acl-support that would be hinted at in the error. 

This will also aid distributors, who would find at build stage (without
needing to specify options) if ACL support somehow wasn't going to be
compiled in. 

What do folks think?

(This was raised first in a private forum, but I want to have further
discussion here). 

Thanks,

Andrew Bartlett
-- 
Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org