Cross compiling samba 4.1

[Andrew Bartlett]

On Wed, 2014-01-15 at 11:02 -0300, Gustavo Zacarias wrote:
> On 01/15/2014 10:12 AM, Stefan (metze) Metzmacher wrote:
> 
> > I think the first target should be 'master' from there we can do
> > backports to
> > 4.1 if want to.
> 
> The patches seem to apply to both branches so i think everyone will be
> happy.
> I haven't tried making master build but i shouldn't be a problem.
> 
> >> 1) python_LIBDIR & friends
> >> As Christophe said in the old thread we can't use the host python for
> >> basically anything useful as it is. At the moment i'm patching python
> >> 2.7.x to include a backport of python's 3.4 python-config script that's
> >> not python-based (shell based, pre-computed results), hence the results
> >> don't depend on a runtime python being runnable (like when cross-compiling).
> > 
> > Would it be possible to get real answers by calling python with the
> > --cross-execute
> > emulator or get the result from the --cross-answers file?
> 
> --cross-answers is probably the way to go.
> 
> >> 3) Heimdal
> >> After some twiddling i managed to get a mixed solution for this.
> >> Since the tools are built for the target and they're needed to build the
> >> libraries i opted to build a host-variant in buildroot and make the
> >> samba build system use the external tools.
> >> It may be possible to avoid this using some CC_FOR_BUILD trickery.
> > 
> > In our old pre waf buildsystem we used to have a HOST_CC, with
> > HOST_CFLAGS...
> > we already have use_hostcc=True, but it's unused currently.
> 
> External heimdal libraries need their own set of patches to
> cross-compile properly, some are already upstream and others need some work.
> I haven't managed to get samba to use those yet, but i'm not handling it
> as a high priority either since in many cross build systems heimdal
> isn't packaged.
> Yes, HOST_ variants should be good too, i'll look into it to avoid the
> need for external heimdal tools.
> 
> >> Of course other proposed ways are welcome, i've got all the necessary
> >> bits to test the results :)
> > 
> > What we need a is a good description of how to reproduce your results,
> > can you update/extend the wiki articles on cross-compiling if needed?
> 
> At the moment i've got this building with buildroot, so it's very
> BR-specific to document i think.
> But yes, once the details are ironed out i can update the wiki.
> Regards.

Thank you so much for taking this challenge on.  This has become quite a
serious issue for an important set of users, but sadly not one we have
been able to get stuck into ourselves.  We really appreciate this being
fixed up.

I wonder if it would be possible to create some kind of test for this,
that works (some of) the cross-compile code path without needing a full
build-root?  That would help avoid regressions in this area.

Thanks,

Andrew Bartlett

-- 
Andrew Bartlett                       http://samba.org/~abartlet/
Authentication Developer, Samba Team  http://samba.org
Samba Developer, Catalyst IT          http://catalyst.net.nz/services/samba