makefile cleanup with Kbuild

[thehajime]

I created a dedicated topic branch for this issue.

https://github.com/libos-nuse/net-next-nuse/tree/kbuild-makefile

I'm also working to solve this issue, patches are highly appreciated !!!

the specific challenges here for LibOS to be on Kbuild system are:

• we need to pick specific object files which is needed for our LibOS line 58 of arch/lib/Makefile (https://github.com/libos-nuse/net-next-nuse/blob/kbuild-makefile/arch/lib/Makefile#L58) is the part of this selection.
• usual conventions like core-y or obj-y is not able to use as-is
• we don't have a system call table at this moment: scripts/checksyscalls.sh reports tons of warnings

reference: http://www.spinics.net/lists/linux-mm/msg87029.html

[thehajime]

9baf2cb35f76629c79a2889c2a81e9445618043b and 32b619181ddd97e84dcb1ec44f9fffcd6c06c726 were the first trial, but not get reached the goal. will try later.

http://www.spinics.net/lists/linux-mm/msg87029.html also recommended: current shape doesn't have dependency checks among the build files.

[thehajime]

dependency detection is implemented with c06025113026c1651eb089a877a1a835ec7915b0, by using Kbuild .cmd files infrastructure. fixed and closed this issue.