The package can be downloaded from Atmel here.

Once you have the gcc arm toolchain installed this pretty much compiles cleanly, except in the output I noticed it trying to cleanup using a cs-rm command. A quick google search discovered this is the legacy code sourcery rm command. I just added link for cs-rm to my /usr/local/arm-gcc/bin directory :
ln -s /bin/rm /usr/local/arm-gcc/bin/cs-rm

The alternative is to find and replace all instances on cs-rm with just rm, but I’d have to do that everytime I update the software package, so I settled on just linking cs-rm to rm.