Ok, it has been a long time since my last play-around with Arduino. This time, I tried to build a simple IR controller to open and close a window shader that I am planing to build. So I copy a sample program and test it out and get the error “TKD2 not defined” error in the following line of code in the file IRremoteTools.cpp which is part of the IRremote library.
int RECV_PIN = TKD2; // the pin the IR receiver is connected to
The simplest solution for this problem turned out to be just delete the two files IRremoteTools.cpp and IRremoteTools.h from the library directory. These two files just provide some additional function interface to the library which I am quite happy to live without them.