bug#49901: Bug in build c-ares [too many loops]

[Nick Bowler]

On 2021-08-17, Brad House via Bug reports for Automake
<bug-automake@gnu.org> wrote:
> I'm one of the maintainers of the c-ares project at
> https://github.com/c-ares/c-ares and have had a couple of users report
> this issue.

I took a quick glance and I found this:

  https://github.com/c-ares/c-ares/blob/main/m4/zz60-xc-ovr.m4

which is redefining autoconf-supplied macros (AC_CONFIG_MACRO_DIR) and
is almost certainly the cause of your problem.  I suggest simply not
doing that, and aclocal will probably work as expected.  Just delete
this file and delete the XC_OVR_ZZ60 line from configure.ac and I
expect your aclocal failure will go away.

The likely reason why the issue is intermittent is because aclocal
will not see this definition on its first pass of a clean workspace,
and the "too many loops" error happens because the state changes in
the middle of the aclocal run, once the redefinition is incorporated
into aclocal.m4 (and things might even appear to work again after
that point, until you delete aclocal.m4 and go again).

If you really need something like this to support bootstrapping with
Autoconf 2.57 (which is getting close to 20 years old now!), I suggest
you find another solution that doesn't involve redefining the internals
on newer Autoconf versions.

Cheers,
  Nick