Before building the kernel you need ramdisk and recovery images. Mine (for KitKat/Vanir) are here:
https://github.com/mkaluza/ste-ramdisk-vanir

clone this and run 'make' inside. In the toplevel dir you'll find boot.cpio and recovery.cpio - copy them to usr/u8500_initramfs_files/ in kernel source tree.

That's it.

Now set CROSS_COMPILE variable to where your toolchain is
export CROSS_COMPILE=/temp/arm-linux-androideabi-4.8/prebuilt/linux-x86/bin/arm-linux-androideabi-
(change the path of course)

As a test, try running ${CROSS_COMPILE}gcc from the command line - if it says "GCC 4.something", you're all set. If it says "no such file or directory", then look closely  at the path it displayed and check again.

Go to kernel source dir and type 'make XXX', where XXX is one of:
- mk_release_noswp_defconfig
- mk_release_swp_defconfig
- mk_debug_defconfig
(if you don't know which one to choose, you want the first one)

It'll prepare the config file - after that just run 'make -j4' and it should build.

(TODO - the rest)