BusyBox

wget http://busybox.net/downloads/busybox-1.22.1.tar.bz2
tar -xjf busybox-1.22.1.tar.bz2
cd busybox-1.22.1/
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- defconfig
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- menuconfig
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- 
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- install CONFIG_PREFIX=/home/export/rootfs

GLIBC

wget http://ftp.gnu.org/gnu/libc/glibc-2.19.tar.gz
tar -xzf glibc-2.19.tar.gz
mkdir glibc-build
cd glibc-build/
./configure --target=arm-linux-gnueabi --prefix= 
make install install_root=/home/export/rootfs 

mkdir proc sys dev etc etc/init.d

Create a file called etc/init.d/rcS and add:

#!bin/sh
mount -t proc none /proc
mount -t sysfs none /sys
/sbin/mdev -s

and make executable:

chmod +x etc/init.d/rcS