[RFC, 1/2] scripts/kconfig/Makefile: Allow KBUILD_DEFCONFIG to be a target

[Olof Johansson]

On Fri, Oct 2, 2015 at 12:47 AM, Michael Ellerman <mpe at ellerman.id.au> wrote:
> On Wed, 2015-23-09 at 05:40:34 UTC, Michael Ellerman wrote:
>> Arch Makefiles can set KBUILD_DEFCONFIG to tell kbuild the name of the
>> defconfig that should be built by default.
>>
>> However currently there is an assumption that KBUILD_DEFCONFIG points to
>> a file at arch/$(SRCARCH)/configs/$(KBUILD_DEFCONFIG).
>>
>> We would like to use a target, using merge_config, as our defconfig, so
>> adapt the logic in scripts/kconfig/Makefile to allow that.
>>
>> To minimise the chance of breaking anything, we first check if
>> KBUILD_DEFCONFIG is a file, and if so we do the old logic. If it's not a
>> file, then we call the top-level Makefile with KBUILD_DEFCONFIG as the
>> target.
>>
>> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
>> Acked-by: Michal Marek <mmarek at suse.com>
>
> Applied to powerpc next.
>
> https://git.kernel.org/powerpc/c/d2036f30cfe1daa19e63ce75

This breaks arm64 defconfig for me:

mkdir obj-tmp
make -f Makefile O=obj-tmp ARCH=arm64 defconfig
... watch loop of:
*** Default configuration is based on target 'defconfig'
  GEN     ./Makefile



-Olof