Just to add, there should be some help on compilation in the readme: https://github.com/espruino/Espruino
There's also a thread on it here: http://forum.espruino.com/conversations/151/
@Gordon started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Just to add, there should be some help on compilation in the readme: https://github.com/espruino/Espruino
There's also a thread on it here: http://forum.espruino.com/conversations/151/