Re: New feature in AC_PROG_CHECK

[Mohammad Akhlaghi]

Dear Autoconf maintainers,

I just wanted to say that I found a work-around for this problem:

http://git.savannah.gnu.org/cgit/gnuastro.git/commit/?id=f0a4d1eec72ae

In short, at the start of the configure script, I remove all occurances 
of the current directory from `PATH'.

The root of the problem before was that the PATH of these users 
contained the current directory (one as `.' and the other as `./', this 
lead to the different names of `./libtool' and `.//libtool'). So I 
thought correcting the PATH would be a more fundamental solution to this 
particular problem.

But generally, even though this particular problem is fixed, it may be 
good if multiple names could be given to `[REJECT]' in `AC_CHECK_PROG' 
(a shell loop).

Thank you very much for all the hardwork on this vital package,

Cheers,
Mohammad

On 12/11/2017 05:19 PM, Mohammad Akhlaghi wrote:
> Hi Autoconf maintainers,
>
> In the `configure.ac' of GNU Astronomy Utilities (Gnuastro), I need to 
> check if `libtool' is present on the system or not (independent of the 
> libtool that is shipped with Gnuastro and is used for its internal 
> building) [P.S1]. Therefore, I use
>
> AC_CHECK_PROG(has_libtool, libtool, [yes], [no])
>
> Recently a user reported that while they didn't have libtool on their 
> system, this test had passed. From `config.log', I could see that it had 
> found (`.//libtool'). Upon further investigation, I found out that it 
> was because his PATH included the current directory and for some reason, 
> it was finding Gnuastro's internally built Libtool [P.S2].
>
> So I updated the command above to this:
>
> AC_CHECK_PROG(has_libtool, libtool, [yes], [no], , .//libtool)
>
> But today, another user reported a similar problem and when I looked at 
> their `config.log' I found out that on that system, it had found 
> `./libtool'! So I changed the command to this:
>
> AC_CHECK_PROG(has_libtool, libtool, [yes], [no], , .//libtool ./libtool)
>
> But looking at the configure script, I noticed that the last argument to 
> AC_CHECK_PROG must only be a single file, not multiple. The only 
> solution that I have come up with so far is call it two times like below.
>
> AC_CHECK_PROG(has_libtool, libtool, [yes], [no], , ./libtool)
> AC_CHECK_PROG(has_libtool, libtool, [yes], [no], , .//libtool)
>
> I wanted to consult you on the best way forward.
>
> I also wanted to see if it would be possible to allow the last argument 
> to AC_CHECK_PROG to accept multiple file names, not just one? In this 
> way, a form like my first try would work and it would also be much more 
> efficient.
>
> Thank you very much,
> Mohammad
>
>
>
> P.S1. Libtool is necessary for one of Gnuastro's programs to work: 
> BuildProgram (see link below). After installation, it uses the user's 
> system's libtool to fix complications with include file and library 
> directories. The description is given here:
>
> https://www.gnu.org/software/gnuastro/manual/html_node/BuildProgram.html
>
>
>
> P.S2. Gnuastro does come with its own implementation of libtool (built 
> from `libtool.m4). But it is strange that the configure script has found 
> libtool in the current directory. Because at least on my system, the 
> configure script builds `libtool' from `libtool.m4' after all the checks 
> not before it. But any way, this is besides the main point here.

--
Postdoctoral research fellow,
Centre de Recherche Astrophysique de Lyon (CRAL),
Observatoire de Lyon. 9, Avenue Charles André,
Saint Genis Laval (69230), France.