Add a recent kconfig version to coreinfo, in order to make the

Add a recent kconfig version to coreinfo, in order to make the
supported features configurable later (currently unused). Store all
build files and results (coreinfo.elf) in build/ now.

I'm self-acking this as (though non-"trivial") it doesn't affect coreinfo
in its functionality, this is more or less a "cosmetic" change to the
build interface ("make" -> "make menuconfig && make").

This is a kconfig checkout from the Linux kernel (where kconfig is being
actively maintained) from 03/2008. The hash identifying the last commit
to kconfig is 587c90616a5b44e6ccfac38e64d4fecee51d588c.

The amount of changes to kconfig itself has been kept as small as possible
to keep the diff small and to ease updating/porting to newer kconfig versions.
The following changes were performed on the upstream Linux kconfig:

 - s/kernel/coreinfo/, and s/Linux/coreinfo/ in various strings.

 - Consistently use the env. variable KERNELVERSION in all kconfig
   interfaces -- e.g. config/menuconfig/gconfig/xconfig -- as version number.

 - Hardcode our paths/filenames in some places (could be improved upstream).

 - Always write .config and build/config.h, no matter which kconfig
   interface is used (config/menuconfig/gconfig/xconfig). We want to
   include build/config.h in our code.

 - Adapt the kconfig Makefile for our purposes (build/ directory, rules, etc).

In addition, a few items in the coreinfo Makefile are needed for this to work.

This kconfig setup is successfully tested with all targets from 'make help':

  config          - Update current config utilising a line-oriented program
  menuconfig      - Update current config utilising a menu based program
  xconfig         - Update current config utilising a QT based front-end
  gconfig         - Update current config utilising a GTK based front-end
  oldconfig       - Update current config utilising a provided .config as base
  silentoldconfig - Same as oldconfig, but quietly
  randconfig      - New config with random answer to all options
  defconfig       - New config with default answer to all options
  allmodconfig    - New config selecting modules when possible
  allyesconfig    - New config where all options are accepted with yes
  allnoconfig     - New config where all options are answered with no

For 'make defconfig' to work you have to do (which we don't need in coreinfo):

  $ mkdir configs; touch configs/defconfig

You can also use 'make foo_defconfig' in which case kconfig will use a
file called 'configs/foo_defconfig' as basis.

Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3188 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1