a question on linux header extraction

[Chan Kim]

Hello,

I'm using linux3.3 and recently while building busybox for a new command, found the BB uses linux kernel headers.
So I looked up the internet and did 'make headers_install ARCH=.. CROSS_COMPILE=.. INSTALL_HDR_PATH=..'.
Then I used the new header files instead of files under sparc-snake-linux/sys-include.
But I had to copy over some missing files from the sys-include to the new header directories and had to copy some missiong definitions from the sys-include files to the corresponing file in the new header files.
Is this what I am supposed to do? (why are there some missing files? Doesn't it work well for versions later than 2.6?) 
And do I have to build the glibc again with this new header files? (I'm using glibc for busybox)
any help would be deeply appreciated.

Thanks
Chan