[coreboot] build.h dependency

[Peter Stuge]

Patrick Georgi wrote:
> > Please talk a little more about this build.h again? I think it's a
> > pretty unclean thing to deal with in mainboard directories.
> 
> I think we can get rid of that rule in mainboard directories
> altogether. Would that fix it?

I think that would be a great improvement already!


> > Does it affect only romcc boards or only car boards or both?
> 
> All boards.

Thanks for clearing that up.


> > How can we get rid of build.h completely?
> > (Yes, I know I asked before.)
> 
> What happens in the build:
> kconfig generates config.h, which carries all the CONFIG_* definitions.
> The build.h file is created by make rules and contains a couple more
> definitions, mostly those with COREBOOT_*, and an include of config.h.

Aha. Could we get COREBOOT_* into config.h somehow?

Maybe add functionality to Kconfig so that it adds all environment
variables with a certain prefix to config.h?


> There's no simple way to force make to wait for this file to be
> created except by telling it that _all_ files depend on it.

Of course. I think it would be nice to get rid of build.h completely
and only have config.h with everything that is neccessary?


> Another approach to solve this conflict (apart from making everything
> depend on build.h) would be to generate build.h on config time. Not
> sure if that leads to desired results.

How is the stuff in build.h used exactly?


//Peter