Currently the only supported build tool is avr-gcc, which is used by the native Arduino SDK.
Other platforms however, such as the ESP32, use different build tools (xtensa in the case of ESP32).
These should also be supported.

One way to allow this is to give the user the ability to pass the name/pattern of the build tool to the framework, which will use it in the Toolchain file when finding all required build tools (such as compilers).
Another option is to add support specifically for ESP32, since it's a very different platform, but that's probably not the preferred option as it's not robust enough.

Edit: Depends on #12.