I am trying to build firmware v18. I have installed the Arduino fork and downloaded the v18 release zip. When I make I get an error while building PCInterrupt.o
PCInterrupt.cpp:42:4: error: ‘PCMSK1’ was not declared in this scope
&PCMSK1,
^
PCInterrupt.cpp:43:4: error: ‘PCMSK2’ was not declared in this scope
&PCMSK2
^
Makefile:408: recipe for target 'PCInterrupt.o' failed
make: *** [PCInterrupt.o] Error 1
Any ideas?