[Buildroot] [PATCH v3 2/5] package: add generic support for lz archives

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Hello,

On Thu, 16 Feb 2017 09:36:28 +0100, Thomas De Schampheleire wrote:

> > Since there is already the exact same pattern for XZCAT, I decided to
> > apply your patch anyway. I also don't really understand the use case
> > for all those BR2_ZCAT, BR2_BZCAT, BR2_XZCAT, etc. config options.
> > Peter, maybe you can shed some light on why we have these?  
> 
> The background for the xzcat case is **drumroll** old RHEL machines
> which do not have xz.
> If the host does have xzcat, then the definition of XZCAT from the
> config is used.
> If the host does NOT have xzcat, then buildroot is instructed to build
> it for us, as a host package, and the result will be set in
> $(HOST_DIR)/usr/bin/. This is the reason for the 'hardcoded' path. In
> this scenario, the variable XZCAT from Makefile does not point to
> something valid.

Thanks for the reminder, but I believe I already knew all of this, and
it's not really the point of my concern/question.

> The reason why in general we have config options for some tools like
> git, zcat, etc. is to let the user decide what they should be. This is
> not only to be able to add certain options, but also because the user
> may want to point to a differently named tool with the same behavior.

Right but the various BR2_{GZIP,XZCAT,LZCAT,...} options also encode
options passed to these programs, not only the path to them. If it was
just the path to them, I wouldn't have a problem at all with this being
ignored if Buildroot builds its own host-xz or host-lzip.

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com