Re: avoiding obsolete macros like AC_TRY_RUN

[Jim Meyering]

Ralf Wildenhues wrote:
> * Jim Meyering wrote on Tue, Sep 01, 2009 at 08:19:55AM CEST:
>>
>> I'd welcome patches to modernize the m4/*.m4 files under my care.
>> Since I tend to use gnulib's files as models, it's worthwhile to
>> update them to use macros that aren't listed as "obsolete".
>
> OK, here we go.  This patch is for modules that you maintain or
> co-maintain.
>
> I removed uses of AC_TRY_{CPP,COMPILE,LINK,RUN}, replacing it with
> the m4-semantic equivalent, double-m4-quoted, code.  In a couple of
> cases, I have improved the quoting of the surrounding code, too.
> This means your code may not work with Autoconf older than 2.55
> (sic! 7 years old), even if it did so before.

No one here even dreams (bad dream!) of supporting such an old
version of Autoconf.

> I have tested the patch by running
>   gnulib-tool --with-tests --test
>
> and ensuring that the resulting configure script has differences only in
> white space and within comments.

That's good enough for me, though I did look through the patch, too,
of course.

...
> Remove obsolete macros in Jim's modules.

Nice work!
You're welcome to apply that.
However, please write more in the log, e.g.,
this subject is more accurate:

    Replace uses of obsolete autoconf macros in Jim's modules.

Also, explaining "why" may help encourage others to switch and/or
to stop people from using the remaining AC_TRY_ macro uses as models.
So please write something like this in the ChangeLog and commit log:
[addressing the two FIXME notes]

    The autoconf macros, AC_TRY_CPP, AC_TRY_COMPILE,
    AC_TRY_LINK and AC_TRY_RUN have been obsolete since ??? FIXME,
    and each use can evoke a warning from autoconf when run
    with warnings enabled.  They were declared obsolete for
    good reasons (see documentation? FIXME), and we should not
    continue using the deprecated macros.

Thank you, Ralf!