[Buildroot] [RFC] [PATCH v2 2/2] support/kconfig: Bump to kconfig from Linux 4.17-rc2

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

Arnout, Thomas, All,

On 2018-05-22 23:22 +0200, Arnout Vandecappelle spake thusly:
> On 20-05-18 16:50, Thomas Petazzoni wrote:
> > Hello,
> > 
> > On Sun, 20 May 2018 16:41:41 +0200, Yann E. MORIN wrote:
> > 
> >> I initially did not reply further to this part, becuase I seem to
> >> remember that there was a change in behavious with certain versions of
> >> flex/bison, that made the output change drastically, and I was afraid we
> >> could be bitten by this...
> >>
> >> But in the end, this is not a problem, because we would not care to
> >> mix-n-match files built with different versions of said tools, as they
> >> would be those from the distro, always, and never those we ship, since
> >> we would no longer ship them.
> >>
> >> And eventually, I now remember that the issue was with gperf changing
> >> its API (a function prototype changed), and that was causing pain. But
> >> now, kconfig no longer uses gperf to start with, so no incompatibility
> >> anymore anyway.
> >>
> >> Which would allow us to drop the dependency of linux on host-{flex,bison}
> >> that we had to add recently.
> > 
> > If we start relying on the system-installed flex and bison, then we
> > should remove host-flex and host-bison entirely, not only for the linux
> > package. The question is whether bison and flex both behave in a
> > reasonably similar way regardless of which version is used.
> 
>  I briefly looked at this in Paris, and it became clear very quickly that even a
> minor change in the bison version would give a completely different .c file. If
> this is a source file that will be built for the target, it's going to be a
> major reproducibility-killer. So I don't think we can remove host-bison and
> host-flex.

We're only talking about dropping the need for host-flex and host-bison
for the kconfig stuff. In this case, we don;t care that the user
generates C code one way or another: it's only a host tool...

Regards,
Yann E. MORIN.

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