Crosstool-NG

You can build toolchains from source code using crosstool-NG.

Follow the steps on the crosstool-NG website to prepare your host.
Follow the Zephyr SDK with Crosstool NG instructions to build your toolchain. Repeat as necessary to build toolchains for multiple target architectures.

You will need to clone the sdk-ng repo and run the following command:
```
./go.sh <arch>
```
Note

Currently, only i586 and Arm toolchain builds are verified.
Set these environment variables:
- Set ZEPHYR_TOOLCHAIN_VARIANT to xtools.
- Set XTOOLS_TOOLCHAIN_PATH to the toolchain build directory.
To check that you have set these variables correctly in your current environment, follow these example shell sessions (the XTOOLS_TOOLCHAIN_PATH values may be different on your system):
```
# Linux, macOS:
$ echo $ZEPHYR_TOOLCHAIN_VARIANT
xtools
$ echo $XTOOLS_TOOLCHAIN_PATH
/Volumes/CrossToolNGNew/build/output/
```