we are using linaro gcc cross compiler,

getting the binary form of GCC from an official source is preferred.

==install pre==
 apt-get -y install build-essential libgphoto2-2:i386 libsane:i386 libgd2-xpm:i386 ia32-libs-multiarch uboot-mkimage lzop ncurses-dev
 apt-get -y install bc build-essential device-tree-compiler lsb-release lzma lzop fakeroot u-boot-tools ia32-libs ccache


===ubuntu 14.04 64bit===
 apt-get -y install libstdc++6:i386 bc build-essential u-boot-tools lzop ncurses-dev device-tree-compiler lsb-release lzma lzop fakeroot u-boot-tools  ccache

===buildroot needs===
 apt-get -y install flex texinfo

==dl the actual cross compiler==

https://launchpad.net/linaro-toolchain-binaries/

https://launchpad.net/linaro-toolchain-binaries/trunk/2013.04/+download/gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux.tar.xz

===installation===


===2013.04===
 cd /opt
 wget https://launchpad.net/linaro-toolchain-binaries/trunk/2013.04/+download/gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux.tar.xz
 tar xvfJ gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux.tar.xz
 echo "PATH=/opt/gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux/bin:${PATH}" >> ~/.bashrc


===2013.06 gcc4.8===
 cd /opt
 wget https://launchpad.net/linaro-toolchain-binaries/trunk/2013.06/+download/gcc-linaro-arm-linux-gnueabihf-4.8-2013.06_linux.tar.xz
 tar -xf gcc-linaro-arm-linux-gnueabihf-4.8-2013.06_linux.tar.xz
 echo "PATH=/opt/gcc-linaro-arm-linux-gnueabihf-4.8-2013.06_linux/bin:${PATH}" >> ~/.bashrc

==path==
 /opt/gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux/arm-linux-gnueabihf/bin
 /opt/gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux/bin