Whitefield is added as a TARGET platform in Contiki (forked version) of the code. The whitefield integration code can be found in the forked version at this location.
Any contiki application can be compiled for whitefield execution by just specifying 'make TARGET=whitefield'.
The default setup makes use of examples/ipv6/rpl-udp application.
Please note Whitefield has not been tested with the Contiki-NG fork.
Whitefield is integrated in RIOT as a third party package. Check the code here.