[Buildroot] [PATCH v3 2/6] Add documentation for merged defconfigs

[Samuel Mendoza-Jonas <sam@mendozajonas.com>]

On Tue, 2016-07-05 at 14:32 -0500, Patrick Williams wrote:
> On Fri, Jul 01, 2016 at 03:18:58PM +0200, Romain Naour wrote:
> > Hi Sam,
> > 
> > This series has been discussed with other developers and we concluded that this
> > feature is not the responsibility of Buildroot to generate a defconfig from
> > partial configuration files.
> > 
> > Instead we recommend to use merge_config.sh from outside of Buildroot to
> > generate the merged defconfig before calling make. Maybe we should add some
> > documentation in the manual to explain how to use it.
> > 
> > Best regards,
> > Romain
> > 
> 
> Earlier we had two independent patch sets that we were asked to merge.
> 
>    1) Merged defconfigs (now this patch set).
>    2) Subdirs for defconfigs.
> 
> If #1 has been rejected as undesireable, should we now prepare an
> indepenent patch set for #2 or is that also not wanted now?
> 
> There is currently no way for us to manage this behavior in a
> BR2_EXTERNAL layer alone because there is no Makefile from the
> BR2_EXTERNAL path sourced in the defconfig case.  Is there any issue
> with a patch that will source a file like $(BR2_EXTERNAL)/external-defconfig.mk?

Actually there might be - Sam was telling me yesterday that the main
Makefile includes?$(BR2_EXTERNAL)/external.mk, which is something we may
use to get mergeconfigs in op-build. That might work for nested configs
as well.

> 
> I realize we could have a new script, but we already have users that are
> use to 'make <system>_defconfig && make' so we would like to be able to
> preserve that behavior even though we are moving to merged defconfig
> fragments.
>