Download xulrunner from here:
https://ftp.mozilla.org/pub/xulrunner/releases/3.6.28/runtimes/
And unpack somewhere
Add this lines to Defold.ini
-Dorg.eclipse.swt.browser.DefaultType=mozilla -Dorg.eclipse.swt.browser.XULRunnerPath=<path to xulrunner directory>
To fix git integration:
sudo apt-get install libssl0.9.8