build a gcc i686 toolchain with crosstool-ng

git clone https://github.com/crosstool-ng/crosstool-ng.git
cd crosstool-ng
./bootstrap
./configure --prefix=$HOME/install/crosstool-ng
make install
echo 'export PATH="${PATH}:$HOME/install/crosstool-ng/bin"' >>~/install/crosstool-ng/crosstool-ng.env

. ./install/crosstool-ng/crosstool-ng.env
mkdir -p ~/workdir
cd ~/workdir
ct-ng list-samples
ct-ng i686-ubuntu16.04-linux-gnu
ct-ng menuconfig
nice -19 ct-ng build.4

ls ~/x-tools/i686-xg-linux-gnu/

Raspberry Raspbian pre-built toolchains

raspberrypi/tools on github

download tools-master.zip

cd /tmp
# I'm using i686 the directory depend on host architecture (32/64 bit)
unzip ~/Downloads/tools-master.zip "tools-master/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/*"
mv tools-master/arm-bcm2708 ~/toolchains/raspberry-pi/
export PATH=$HOME/toolchains/raspberry-pi/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin:$PATH

test.cpp:

#include <iostream>
int main(int argc, char **argv)
{
   std::cout << "hello world" << std::endl;
   return 0;
}

run test on rpi:

arm-linux-gnueabihf-g++ -Wall -O2 -o test test.cpp
scp test pi@rpi-host:/tmp
ssh pi@rpi-host
/tmp/test
$ hello world