FWIW, on a fresh ubuntu 16.04 install, this is what needs to be run: sudo apt update && sudo apt install python build-essential -y wget -O bootstrap.py

FWIW, on a fresh ubuntu 16.04 install, this is what needs to be run: sudo apt update && sudo apt install python build-essential -y wget -O bootstrap.py https://hg.mozilla.org/mozilla-central/raw-file/default/python/mozboot/bin/bootstrap.py && python bootstrap.py cd mozilla-unified/ ./mach build