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Bug#766708: Processed: Re: Bug#766708: breaks multiarch cross building

Helmut wrote:
> On Wed, Nov 19, 2014 at 04:41:49PM -0800, Don Armstrong wrote:
> > Are people who are doing cross-building like this actually using the
> > code which will be in jessie? I (perhaps naïvely) would expect them to
> > be primarily using the code in unstable, and maybe at a late stage of
> > bring-up rebuilding all of stable.
> Thanks for asking this. Let me give two answers to this question:
> 1) No. The continuous integration happened in sid and people
>    bootstrapping new architectures tend to use sid plus patches. However
>    the method of bootstrapping that was known working two weeks before
>    the freeze no longer works. Whatever method is going to be used now,
>    it requires changing packages. Since these changes tend to not fall
>    under the freeze policy, they are practically not mergeable. So in
>    this answer, jessie is to be understood as a time frame: Keep things
>    working that worked before until we are allowed to fix things.
> 2) Yes. People repeatedly ask for cross toolchains on stable systems.
>    This is the very reason why Wookey tried to package them for jessie.
>    Ultimately, they ended being late, so people will try to build them
>    on their own and for the popular targets (mostly armhf, armel) this
>    actually worked.

We've been using this for development of embedded systems where building
on native hardware (or in an emulator) is ridiculously slow (or even
impossible for some devices) compared to cross building from Debian on
more powerful hardware.

That worked great for all releases up to and including Squeeze.

For Wheezy, the late introduction of multi-arch basically broke that
and doing this on that release was effectively impossible.

The change which was reverted here had made doing that on Jessie possible
once again, and made it a relatively trivial matter to build your own
cross-toolchain using the packaged gcc source (in the absence of those
being able to actually be uploaded as pre-built binaries yet).

I'd be kind of sad if that stopped being possible again for the final
released version of Jessie, and we had to skip yet another release
before being able to do this on Debian again.  It may not be the best
and final answer, but it has some advantages over the proposed
alternative, like being able to work with existing m-a packages
without needing to rebuild custom versions of everything, and actually
working on Debian today.

It's not clear to me what advantage was gained by removing it before
the alternative to it is actually viable to use, or what problem it
had that made doing that compelling.

Unless someone can show me that, I'd definitely prefer to have this
functionality restored again for Jessie.  It's definitely desirable
to have this on a stable system, since the lock-step requirement of
m-a makes it rather more painful to keep this all working on an
unstable system where packages are changing rapidly (and because
stable deps are kind of an important thing too :)


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