[Buildroot] [PATCH] prevent recursion in %_defconfig rules

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

J?r?my, All,

On 2014-01-17 18:52 +0100, Yann E. MORIN spake thusly:
> On 2014-01-07 17:22 +0100, J?r?my Rosen spake thusly:
> > Signed-off-by: J?r?my Rosen <jeremy.rosen@openwide.fr>
> > 
> > ---
> > The following command, run from a clean buildroot checkout
> > 
> > make O=.. BR2_EXTERNAL=.. raspberrypi_defconfig
> > 
> > cause the following output, and makes stop :
> > 
> > 
> > make: *** Pas de r?gle pour fabriquer la cible ? /home/rosen/tmp/buildroot/
> > configs/../configs/../configs/../configs/<lots more >/../configs/
> > raspberrypi_defconfig ?, n?cessaire pour ? /home/rosen/tmp/buildroot/
> > configs/../configs/../configs/<lots more>/../configs/
> > raspberrypi_defconfig ?. Arr?t.
> > 
> > The problem is that the buildroot makefile has two rules to generate
> > %_defconfig: One that depends on $(TOPDIR)/configs/%_defconfig and the
> > other one that depends on $(BR2_EXTERNAL)/configs/%_defconfig.
> > 
> > When one rule checks for the file, the other rule becomes an implicit rule
> > for the dependancy causing an infinite cross-recursion.
> > 
> > By overriding the implicit rule, we prevent the infinite recursion.
> 
> This breaks defconfigs from BR2_EXTERNAL when used with an out-of-tree
> build:
> 
>     make -C /path/to/buildroot              \
>          O=/path/to/build                   \
>          BR2_EXTERNAL=/path/to/br2.external \
>          yem_defconfig
>     [--SNIP--]
>     *** Can't find default configuration "/home/ymorin/dev/buildroot/buildroot/configs/yem_defconfig"!

It even breaks BR2_EXTERNAL for in-tree builds.

Reverting that patch fixes both issues, and does not exhibit the
reported problem.

Peter, can we just revert that patch (cset 94dd02f) for now, please?

J?r?my, can you describe your setup, so we can try to reproduce it, and
find a proper fix?

Regards,
Yann E. MORIN.

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