PX4/Firmware — pull request #1103 by hsteinhaus (2014-06-30 20:52:48+00:00)
Title: UAVCAN: append to EXTRADEFINES to those given by make cmd line

This patch make EXTRADEFINES resistant against overwriting them via make command line. ArduPilot is passing its own EXTRADEFS to make, to make itself known as a PX4 module, that lives outside of the tree. This approach overwrites the defines needed by uavcan.