[Buildroot] [PATCH 3/5] python-cffi: add host variant

[Yann E. MORIN <yann.morin.1998@free.fr>]

Yegor, All,

On 2015-12-25 20:58 +0100, Yegor Yefremov spake thusly:
> On Fri, Dec 25, 2015 at 8:12 PM, Yann E. MORIN <yann.morin.1998@free.fr> wrote:
> > On 2015-12-25 20:00 +0100, Thomas Petazzoni spake thusly:
> >> On Thu, 24 Dec 2015 23:12:49 +0100, Yegor Yefremov wrote:
> >> > Target variant doesn't need pycparser. cffi's setup.py seems to
> >> > distinguish, if we install real package or cross-compiled one:
> >> >
> >> >         install_requires=[
> >> >             'pycparser',
> >> >         ] if cpython else [],
> >>
> >> I don't understand how this "if cpython" is relevant to make the
> >> different between the native (host) variant or the cross-compiled
> >> (target) variant. cpython is defined as is:
> >>
> >>     cpython = ('_cffi_backend' not in sys.builtin_module_names)
> >>
> >> Can you give some more details?
> >
> > Yegor and I briefly discussed this on IRC yesterday, but I'm not really
> > convinced by this reply either. I forgot to reply yesterday...
> >
> > What I understand, however, is that they want to differentiate between
> > cpython (the 'ofiicial' native Python interpreter), and PyPy (the Python
> > interpreter written in Python).
> >
> > Of course, I don't see how this all works. It seems in
> > cross-compilation. there differentiation criterai beliveves it is
> > running under PyPy amd thus they do not need pycparser.
> >
> > But thtat's just incorrect, because we may have a host-python with
> > cffi_backend at one point, and thus the check above will eventually
> > differentiate toward cpython, and we'd nreak again.
> >
> > So, two things:
> >   - their check is wrong,
> >   - we probably need host-pycparser
> >
> > At least, that's what I understood...
> 
> We have host-pycparser: http://patchwork.ozlabs.org/patch/560970/

Well, I meant that we should need host-pycparser as a dependency of
python-cffi.

But anyway, there is more to this: we really need to understand what is
going on...

Regards,
Yann E. MORIN.

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