Re: fyi-ac-arg-var.patch

[Pavel Roskin]

Hi, Akim!

> Once this issue settled, I'm in favor of releasing 2.51.  I know there
> are still bugs, but there is still a long way to walk, and one step
> would be a good thing.

The testsuite must pass when a new version is released. Now it doesn't.
Paul's attempt to make AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS
obsolete causes two failures in the testsuite.

We need a generic solution for obsolete macros. The existing approach with
AU_DEFUN doesn't work in this situation. I really wish that you do
something about it, because AU_DEFUN was your idea.

In fact, the `A' in AU_DEFUN stands for Akim :-)

Let me summarize the problem one more time. AC_SYS_RESTARTABLE_SYSCALLS is
a more complicated case, so let's concentrate on it.

I believe that we should satisfy the following requirements:

1) AC_SYS_RESTARTABLE_SYSCALLS should work as before, i.e. it should
expand to the same code in configure. As a consequence ...

2) it should still be possible to use AC_REQUIRE from
AC_SYS_RESTARTABLE_SYSCALLS (it's used now).

3) Use of AC_SYS_RESTARTABLE_SYSCALLS in configure.in should cause a
warning displayed by autoconf (that was the idea of the patch).

4) The testsuite should test AC_SYS_RESTARTABLE_SYSCALLS. Warnings from
autoconf should be either ignored or checked for being non-empty.

5) autoupdate should either leave AC_SYS_RESTARTABLE_SYSCALLS unchanged or
add a comment saying that it's obsolete (the later would have ugly
consequences if autoupdate is run more than once). Maybe it should tell
the user that there is no replacement for AC_SYS_RESTARTABLE_SYSCALLS, and
eliminating it requires manual intervention.

The existing testsuite implies that either a macro causes no warnings or
it's updateable.

Neighter AT_CHECK_MACRO nor AT_CHECK_AU_MACRO is acceptable to test
AC_SYS_RESTARTABLE_SYSCALLS. The former doesn't allow warnings. The later
expects autoupdate to print "autoupdate: `configure.ac' is updated".

The simpleast solution would be to introduce AC_DEFUN_WARNING that would
act like like AC_DEFUN except that mktests.sh would put it to a separate
list of macros tested with, say AT_CHECK_MACRO_WARN, that would make sure
that a warning is produced by autoconf.

Having done that, we could improve autoupdate to print macro-specific
warnings.

-- 
Regards,
Pavel Roskin