Thanks for the replies. Crosspack looked quite old and I'm a homebrew
user, so I ended up finding an unofficial brew formula to build the
avr toolchain and using brew to install the rest too:
git clone
https://github.com/larsimmisch/homebrew-alt.git LibraryAlt
brew install LibraryAlt/avr/avr-libc.rb
brew install avrdude dfu-programmer
The toolchain works, but I'm waiting for my board from NooElec so I
haven't been able to test on hardware yet.