A RPL border router. 
To indicate the hardware target for the border router, add one of the following
options in the command line:
If rpl-border-router runs on dongle:
JN516x_WITH_DONGLE=1
If rpl-border-router runs on DR1174:
JN516x_WITH_DR1174=1
If building for a new platform, first execute : make clean

See ../README.md for more.