Four environment variables are expected (set in .bash_profile), and
sample values:

ARMK_DIR = $HOME/src/3p/Arduino-Makefile
ARDUINO_DIR = $HOME/src/3p/ArduinoCore-avr
ALTERNATE_CORE_PATH=$HOME/src/3p/ArduinoCore-avr
USER_LIB_PATH=$HOME/src/gstein/arduino/libraries

$ apt-get install gcc-avr avr-libc avrdude

Clone the following directories into $HOME/src/3p/ :

https://github.com/sudar/Arduino-Makefile.git
https://github.com/arduino/ArduinoCore-avr.git
https://github.com/gstein/Ethernet.git