bug#8718: error when using nested conditionals

[Stefano Lattarini]

On Friday 10 June 2011, Bruno Haible wrote:
> Peter,
> 
> > how about the following alternative (for all conditionals, or just for some
> > of them, e.g., those under the regime of AM_IGNORE_UNDEFINED_CONDITIONALS):
> > Replace the AC_MSG_ERROR() above by a warning and set both $1_TRUE and
> > $1_FALSE to something that, when not hidden in a false branch of the
> > Makefile, (1) triggers a make syntax error, and (2) contains sufficient info
> > to deduce the cause for that error.
> 
> Sounds good. But gnulib would also need a way to disable the warning,
> because otherwise the maintainers of packages that use gnulib come back to
> me and ask how they can get rid of the warning.
> 
> Bruno
> 
I like Peter proposal too, it's neat and shouldn't be difficult to implement
and document.  But maybe I like Bruno's latest proposal about adding a third
argument to AM_CONDITIONAL even more; see:
 <http://lists.gnu.org/archive/html/bug-automake/2011-06/msg00009.html>
The problem is, how would that scale on more complex situations?  That's not
quite obvious to me.  Peter's proposal seems safer in this regard.

Hmmm, I can't really decide between these two proposals offhand.  Let's wait
a couple of days to see if Ralf can chime in, OK?  Otherwise we'll try to
sort this out ourselves.

For the moment, thank you all for your ideas and contribution.

Regards,
  Stefano