bug#20713: aclocal/tar.m4 and solaris 5.10

[Karl Berry]

    i have no idea what the quoting style/preference is in the GNU world,

Nothing GNU-wide, but among autotools and related packages
written/maintained by approximately the same group of people, I believe
  test x"$foo" = x1
is the most-usual style. Though "x$foo" is common too,
since it makes no difference.

The "test" item, most of the way down in the "Limitations of Shell
Builtins" node of the Autoconf manual, reports a lot of the things that
have led to the common forms/workarounds.
https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/Limitations-of-Builtins.html#Limitations-of-Builtins

Not including the not-quoting of constant strings though, granted,
since that also makes no difference.

I can't recall any other style guide for shell coding conventions, either.


Anyway, back to the bug topic.

    i think there's merit to issuing a warning 

Ok, I yield. No appetite to argue further over this tiny issue.

    configure user can (re)create dist tarballs too.  not the common flow, 
    
Quite an understatement there :).

    the reason your system hit this code path

I was not running make dist. I was just running configure on Solaris 5.10.
As far as I can recall.

   it can be helpful when you're hacking on a system and want to pull
   the state back out.
    
Personally, I would never trust make dist not to alter the state
that it was supposedly snapshotting. But whatever. --thanks, karl.