configure.ac: run autoupdate to fix autoconf warning

This fixes the following warning:

    $ autoconf
    configure.ac:306: warning: AC_OUTPUT should be used without arguments.
    configure.ac:306: You should run autoupdate.

Environment:

    $ grep '^NAME' /etc/os-release
    NAME="Artix Linux"
    $ pacman -Q autoconf
    autoconf 2.71-1

Though keep `AC_PREREQ` at 2.68 (released on 2010-09-23[1]), as version
2.71 (which autoupdate automatically bumps to) is rather recent
(released on 2021-01-28[2]) and the changes do not appear to require a
version bump, as on `AC_INIT` it only adds some quotes, and the rest of
the changes are consistent with the autoconf 2.68 manual.  From Section
18.4, Obsolete Macros[3]:

> — Macro: AC_OUTPUT ([file]..., [extra-cmds], [init-cmds])
>
>     The use of AC_OUTPUT with arguments is deprecated.  This obsoleted
>     interface is equivalent to:
>
>               AC_CONFIG_FILES(file...)
>               AC_CONFIG_COMMANDS([default],
>                                  extra-cmds, init-cmds)
>               AC_OUTPUT
>
>     See AC_CONFIG_FILES, AC_CONFIG_COMMANDS, and AC_OUTPUT.

Note: The usage of the above format has been present since the inception
of configure.ac, on commit 137985136 ("Baseline firejail 0.9.28").

Misc: This is a continuation of #4293.

[1] https://lists.gnu.org/archive/html/info-gnu/2010-09/msg00013.html
[2] https://lists.gnu.org/archive/html/autoconf/2021-01/msg00126.html
[3] https://www.gnu.org/software/autoconf/manual/autoconf-2.68/html_node/Obsolete-Macros.html#index-AC_005fOUTPUT-2058

0 files changed, 0 insertions, 0 deletions