[klibc] Introduce kbuild for klibc?

[Sam Ravnborg]

Hi hpa and others.

With my ongoing work to prepare for potential integration of klibc in
the kernel I wonder if there wold be any interest in using part of the
kbuild infrastructure to build the vanilla klibc?

The rationale is obvious:
- common codebase for Kbuild files, so one only has to fix things in one
  place
- I force klibc developers to create Kbuild files usable in the kernel
- Much nicer output when building ;-)

It would take some effort to move over to kbuild. The main parts being
different names and missing kbuild functionality.

I have a proof-of-concept mucked up already that mostly works.
But it does not support stuff like "clean and spotless" targets etc.

If there is agreement this is a good way to go then I will give it an
extra spin and try to post a few patches.

PS. Still missing feedback on kernel integration...

	Sam