"10 G not enough for building Linux Kernel?" I would do it for less. What's the currency?
I've got two copies of the kernel source, one used as a build environment but / (which has all the OS except for what's on /var and what's in /home) is only using 6.9 GB
c@CW8:~$ df -h /
Filesystem Type Size Used Avail Use% Mounted on
/dev/root jfs 15G 6.9G 7.5G 49% /
That's for Slackware 13.37 plus ~30 extra apps.
EDIT: the build environment itself (after building so with all the binaries) is only 1.3 GB:
c@CW8:~$ du -hs /home/c/src/linux-18.104.22.168/