[Buildroot] [RFC PATCH 1/1] package/automake: include .m4 files of autoconf-archive

[Thomas Petazzoni]

Hello,

On Sun, 13 Aug 2023 14:40:37 +0200
"Yann E. MORIN" <yann.morin.1998 at free.fr> wrote:

> After thinking a bit on this, here's what I think we should try;
> 
> For packages that have _AUTORECONF = YES, we forcibly add
> host-autoconf-archive to their _DEPENDENCIES, and always set the macros
> search path as proposed here. Supposedly, having macros from
> autoconf-archive available should not be a cause for failure to
> successfully autorconf, otherwise that would not work on random systems
> which have it installed for other reasons, like native builds on
> standard distros; also, a missing directorry in the macro search list
> should not be a cause for failure.
> 
> Consequently, we can drop the ad-hoc dependencies in the individual
> packages, and drop the ad-hoc include directove as well.
> 
> host-autoconf-archive is a plain autocnf package, without dependencies
> (save for the autoconf machinery), and it only ever installs a buncha
> files, does not compile anything, so it is pretty fast. Adding it to all
> autoreconfigured packages should have a minimal, barely noticeable
> impact on the build time.
> 
> If the above causes too much breakage, then even this patch was going to
> be incorrect, as it would unconditionally add the autocon-archive path
> to the search list for all packages that indirectly have
> autoconf-archive in their dependencies.

We have 336 packages that set AUTORECONF = YES. Out of these 336
packages, only 8 need host-autoconf-archive.

To me, it makes no sense to add host-autoconf-archive to those 336-8
packages that need autoreconf, but do not use any of the macros
provided by host-autoconf-archive. One of Buildroot's beauty is its
minimalism: it builds only what's needed, and every time it builds
something, there is a solid reason for it. I would really dislike if we
were to start building useless dependencies, even if admittedly
host-autoconf-archive is small and quick to build. But small and quick
to build is not the only thing, it's also about whether it makes sense.
I regularly stare at my build going on, and when something gets built
that I don't understand why its gets pulled into the build, I check
with "make graph-depends" why it is there, and sometimes investigate
further to make sure there's a good justification. To me, this is an
important property of Buildroot, and I would really like to keep this
aspect of Buildroot.

Especially, I don't see what problem we would solve by making
host-autoconf-archive a dependency of all packages that do AUTORECONF =
YES. What problem would this solve?

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com