The linux README file says:
sudo p pixy.rules /etc/udev/rules.d/
It should read:
sudo cp pixy.rules /etc/udev/rules.d/
I also had to do:
sudo apt-get install qt4-default
otherwise qmake tried to use qt5 rather than qt4
I also edited buildpixymon.sh to use:
mkdir -p bin
so that it would work if you ran it a second time.