Build your own ARM cross toolchain from source

I used to have a mac and I want to use it for software development.  I need to build Linux kernel but I couldn't find the ARM cross compiler toolchain for OSX.  If you're in the same situation, you can follow below links to build you own toolchain:

• https://istarc.wordpress.com/2014/07/21/stm32f4-build-your-toolchain-from-scratch/
• http://jeremyherbert.net/get/stm32f4_getting_started