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

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

Hello,

On Wed, 15 Feb 2017 23:48:13 +0100, Arnout Vandecappelle wrote:

> >> +DEPENDENCIES_HOST_PREREQ += host-lzip
> >> ++EXTRACTOR_DEPENDENCY_PRECHECKED_EXTENSIONS += .lz
> >> +LZCAT = $(HOST_DIR)/usr/bin/lzip -d -c  
> > 
> > But here in the case where we are building our own host-lzip, we
> > completely ignore BR2_LZCAT, and use a hardcoded
> > $(HOST_DIR)/usr/bin/lzip -d -c.  
> 
>  Er, yes of course: if BR2_LZCAT doesn't work, then we use the Buildroot
> internal lzcat. What else did you expect?

BR2_LZCAT does not specify only the path to the lzcat program, but also
its options. And we completely ignore those custom options if the
lzcat built by Buildroot is used.

>  As I understand it, these options are provided in case you have an old build
> host and have locally installed these tools in e.g. your homedir. However, I
> wouldn't mind getting rid of these options completely, and instead require that
> they are in PATH.
> 
>  True, they could also be used to pass alternative options to the extractors,
> but I don't see much point of that. Or they could be used to call it in an
> alternative form, e.g. "zcat" instead of "gzip -d -c", or "busybox gzip -d -c".
> But I also don't see much point of that.
> 
>  While we're on the subject, I don't see much point of BR2_TAR_OPTIONS either.
> 
>  But of course, it's not as if keeping these things is such a burden. So I at
> least won't spend time in removing them.

See above why it doesn't make sense to me: BR2_LZCAT allows to specify
not only the path/name of the lzip program, but also its options. And
they get completely ignored when host-lzip is built by Buildroot.

Which means one person doing the build on a machine with lzip installed
locally will have BR2_LZCAT taken into account, and another person
doing the same build on a different machine that does not have lzip
installed will not have BR2_LZCAT taken into account.

This is definitely not very consistent IMO.

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