archlinux makepkg on ubuntu

gistfile1.txt

sudo aptitude install libarchive-dev bsdtar

git clone git://projects.archlinux.org/pacman.git

cd pacman
./autogen.sh
./configure --disable-doc
make
sudo make install

cd package
cp /usr/local/etc/makepkg.conf ./makepkg-arm.conf


makepkg-arm.conf ==================================================

CARCH="arm"


PKGBUILD ==========================================================

pkgname=linux-raspberrypi-custom
pkgver=3.2.27
pkgrel=1
pkgdesc="The Linux Kernel and modules for Raspberry Pi (customized)"
arch=(arm)
url="http://www.kernel.org/"
license=('GPL2')

xtool=/opt/cross/x-tools/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-

build() {
  cd $startdir/../linux
  make ARCH=arm CROSS_COMPILE=$xtool
}

package() {
  cd $startdir/../linux
  make ARCH=arm CROSS_COMPILE=$xtool INSTALL_MOD_PATH=$pkgdir modules_install firmware_install
  mkdir $pkgdir/boot
  cp $startdir/../linux/arch/arm/boot/zImage $pkgdir/boot/kernel.img
}

===================================================================


makepkg --conf ./makepkg-arm.conf

How do I use this?