[bug#71022] [PATCH] configure.ac: Set default value for the 'prefix' variable.

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi Ludovic,

Ludovic Courtès <ludo@gnu.org> writes:

> Hi Maxim,
>
> Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:
>
>> The Guix standard configuration uses a localstatedir of /var and a sysconfdir
>> of /etc.  To ease things for everyone, make the default values match that
>> standard expected configuration.  See
>> <https://lists.gnu.org/archive/html/guix-devel/2024-05/msg00003.html> for a
>> related discussion.
>>
>> * configure.ac: Default $prefix to '' unless already set.
>> * doc/contributing.texi (Building from Git): Streamline doc.
>> * doc/guix-cookbook.texi (Guix environment via direnv): Likewise.
>>
>> Change-Id: I23cd12b58a842d246fbc9fdc740311c573eb0212
>
> [...]
>
>> +dnl Set some sane default directory variables for use with the Guix.  This
>> +dnl also causes localstatedir to be /var and sysconfdir to be /etc.
>> +test "$prefix" = NONE && prefix=
>
> Shouldn’t it read “prefix=/”?

This is what I went for originally, but it would cause this error:

--8<---------------cut here---------------start------------->8---
configure: error: chosen localstatedir '//var' does not match that of the existing installation '/var'
Installing may corrupt /gnu/store!
Use './configure --localstatedir=/var'.
--8<---------------cut here---------------end--------------->8---

So it seems Autoconf's generated configure script expects --prefix to
*not* contain a trailing '/', which is the case for --prefix=/.

> Might be good to check whether this breaks “make distcheck”, so I
> suppose it should be fine.

Good suggestion; I just tested the target and the tarball was
successfully generated.

> Apart from that it LGTM.  Thanks for this patch!

Thanks for reviewing it!  I'll send a v2, and wait for further comments,
if any.

-- 
Maxim