Install ARM Toolchain on Ubuntu

Ubuntu 16.4.3 LTS:

$ sudo apt-get install libc6-armel-cross libc6-dev-armel-cross
$ sudo apt-get install binutils-arm-linux-gnueabi
$ sudo apt-get install libncurses5-dev

for Hard Floating Point CPUs (including a NEOS FPU):

$ sudo apt-get install gcc-arm-linux-gnueabihf
$ sudo apt-get install g++-arm-linux-gnueabihf