yes, it’s for linux. i use windows, no experience with mac, so you’ll need to try and apply the instructions from https://github.com/denravonska/avr32-toolchain. have you seen this section there? (messed up formatting in their readme makes it difficult to see somewhat):
=== Requirements (OS X) ===
You will need to have GCC, make and binutils on your machine to compile all of this. You can get all of these on Mac OS X, by just installing the Apple link:http://developer.apple.com/technologies/tools/[Developer Tools]. You should be able to download free versions of 3.x from the ADC website, install from the OS X install disc that came with your machine, or download XCode 4 from the App Store (now free again for all registered users).
You will also need gmp, mpfr and mpc first. I recommend installing these from link:https://github.com/mxcl/homebrew[homebrew] for now. I’ll add these to the Makefile once I have a consistent configuration that can be used for both Linux & OS X.
With homebrew you can install those dependencies like this:
brew install mpfr gmp libmpc texinfo
If you would like to build dfu-programmer, also install libusb:
brew install libusb-compat