[LTP] [PATCH 2/2] configure.ac: Update AC_PROG_AR related comment

[Petr Vorel]

Hi Zack,

thank you for all your comments, highly appreciated!

> On 2023-01-10 4:25 AM, Richard Palethorpe wrote:
> > > >   AC_PROG_CC
> > > > -# <= autoconf 2.61 doesn't have AC_PROG_AR, but 2.63 has it. Not sure about
> > > > -# 2.62.
> > > > +# autoconf >= v2.72a

> > > This reads like we need the def for autoconf => v2.72a. How about
> > You're right.  I probably thought this is defined since v2.72a,
> > thus not needed.

> Please don't use 'v2.72a' in any commentary or tests.  That version doesn't
> exist yet and may never exist; if it does, it will be a short-lived beta
> test release of v2.72 that we don't want people to depend on.
> (Autoconf uses a very old version numbering convention in which beta tests
> for release X.Y are labeled X.Ya, X.Yb, X.Yc, etc.)

> Officially, AC_PROG_AR will be available as of version 2.72, and that's what
> you should reference in commentary.

I understood v2.72a similarly as kernel -rc1 gained new version.
But sure, makes perfect sense to use final version in the comment.

> > Also it looks like that redefinition is not a problem thus
> > not wrapping with m4_ifndef([AC_PROG_AR].

> Autoconf will let you do that, but it's bad practice.  What if version 2.73
> makes AC_PROG_AR expand to something other than
> AC_CHECK_TOOL(AR, ar, :) ? You'd be overwriting whatever bug fix that was.

> I suggest something like

> # AC_PROG_AR was added in autoconf 2.72.
> m4_ifndef([AC_PROG_AR],
>   [AC_DEFUN([AC_PROG_AR], [AC_CHECK_TOOL(AR, ar, :)])])

> > NOTE: missing 'ar' don't fail configure (isn't the check useless
> > then?)

> We don't know what you need `ar` for; it might not be appropriate to fail
> the build if it's missing.  You can do

> AC_PROG_AR
> AS_IF([test x$AR = x:],
>   [AC_MSG_FAILURE([no usable "ar" program detected])])

> if you want to fail the build.

@Richie @Li, we obviously need ar for libs/, I'd be for this.
I also have look how other check works.

Kind regards,
Petr

> zw