Thirdparty hardware support

If the hardware dependent code for your platform can (or should) for license (or other) reasons not become part of the official RIOT repository, you can still include external folders into the build process. To do this, define the two variables RIOTCPU and RIOTBOARD in your application pointing to the respective directories. For example:

RIOTCPU ?= ../../thirdparty_cpu
RIOTBOARD ?= ../../thirdparty_boards

These directories should have a similar structure like cpu and boards in the main RIOT repository, i.e. contain a sub-directory for each supported MCU/platform.