kbuild: Separate ouput directory support

[Sam Ravnborg <sam@ravnborg.org>]

The following set of patches introduce support for
separate output directory when building a kernel.
Typical usage is building several kernels with different configurations -
but based on the same kernel src.

Consider the following setup:
/home/sam/bk/linux-2.6		<= kernel src

/home/sam/kernel/mars		<= My workstation
/home/sam/kernel/defconfig	<= defconfig for compiletime testing

Then in order to handle the two different configurations I just have to do:
cd /home/sam/bk/linux-2.6
make O=../../kernel/mars

And the same for the defconfig version.

All output files are stored in the output directory, including .config.
[Thanks to Roman Zippel which made this loong time ago in kconfig].

The patch has been in existence in several months but only lately becoming
in a suitable state ready for inclusion. It is developed based on an initial
concept made by Kai Germaschewski, but refined a lot since then.
It works with a kernel based on default configuration (make defconfig).

It is divided up in the following parts:
core	the kbuild changes to support separate output directory
ieee	Fix in ieee Makefile
i386	Fix in i386 Makefiles + new syntax enabled for always
	This was required because i386 had an executable located in
	a subdirectory.
include	Fixes for errornous include paths, and one place where a generated
	.c file references a .h file in the kernel tree.
	

Please pull from
	bk pull bk://linux-sam.bkbits.net/kbuild

Patches follows this mail.

	Sam