Customized Setup of Toolchain
Instead of downloading binary toolchain from Espressif website (see Step 3. Set up the tools) you may build the toolchain yourself.
If you can’t think of a reason why you need to build it yourself, then probably it’s better to stick with the binary version. However, here are some of the reasons why you might want to compile it from source:
if you want to customize toolchain build configuration
if you want to use a different GCC version (such as 4.8.5)
if you want to hack gcc or newlib or libstdc++
if you are curious and/or have time to spare
if you don’t trust binaries downloaded from the Internet
In any case, here are the instructions to compile the toolchain yourself.