[PATCH] scripts/kconfig/Makefile: Fix KBUILD_DEFCONFIG check when building with O=

[Michael Ellerman]

On Thu, 2015-10-15 at 09:27 +0200, Michal Marek wrote:
> Dne 15.10.2015 v 08:05 Michael Ellerman napsal(a):
> > My recent commit d2036f30cfe1 ("scripts/kconfig/Makefile: Allow
> > KBUILD_DEFCONFIG to be a target"), contained a bug in that when it
> > checks if KBUILD_DEFCONFIG is a file it forgets to prepend $(srctree) to
> > the path.
> > 
> > This causes the build to fail when building out of tree (with O=), and
> > when the value of KBUILD_DEFCONFIG is 'defconfig'. In that case we will
> > fail to find the 'defconfig' file, because we look in the build
> > directory not $(srctree), and so we will call Make again with
> > 'defconfig' as the target. From there we loop infinitely calling 'make
> > defconfig' again and again.
> > 
> > The fix is simple, we need to look for the file under $(srctree).
> > 
> > Fixes: d2036f30cfe1 ("scripts/kconfig/Makefile: Allow KBUILD_DEFCONFIG to be a target")
> > Reported-by: Olof Johansson <olof at lixom.net>
> > Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
> 
> Acked-by: Michal Marek <mmarek at suse.com>
> 
> I could have spotted it myself :-/.

It was pretty easy to miss in the diff, especially as the kconfig invocation
doesn't use $(srctree).

I should have noticed it in my testing, but it didn't actually break powerpc,
so the only clue was that the message says "based on target". Anyway fixed now
hopefully.

cheers