[U-Boot] [RFC PATCH 2/2] Makefile: Give a build error if ad-hoc CONFIG options are added

[Stephen Warren]

On 08/24/2016 08:44 AM, Simon Glass wrote:
> New CONFIG options should be added via Kconfig. To help prevent new ad-hoc
> CONFIGs from being added, give a build error when these are detected.

Acked-by: Stephen Warren <swarren at nvidia.com>
Tested-by: Stephen Warren <swarren at nvidia.com>

I worried about the increased build time due to find/grep on all Kconfig 
files, but at least with a hot disk cache it seems to make no noticeable 
difference:-)

FWIW, CONFIG_SPL_GPIO_SUPPORT is missing in the whitelist, which affects 
the Jetson TK1 build (and likely all/most other Tegra boards).

Ah, that's why "CONFIG_" is in the current whitelist; there are 
Makefiles that reference CONFIG_$(SPL)_SOMETHING. Handling that 
automatically might be a little involved for a one-off thing; I guess 
you'd need to manually fix up the whitelist for this?