Updated with Linux information tested on Ubuntu.
Had to install sam-1.6.6 myself, download from ttp://downloads.arduino.cc/cores/sam-1.6.6.tar.bz2 and extract to arduino-1.6.7/hardware/arduino/
Modify platform.txt as with Windows/OSX, but path changes slightly from ARM to GCC: "{build.system.path}/CMSIS/CMSIS/Lib/GCC/libarm_cortexM3l_math.a"
