You may use this tool to create a Firefox Mobile (Fennec) extension (.xpi) from a greasemonkey script.
Type in the appropriate details below, you may leave the default random GUID if you do not have one, or replace it with your own value, which you should definitely do for upgrades to an existing extension.
When pasting in the script, include the ==UserScript== block, as the compiler reads data from there (name, description, includes/excludes).
View Source Code
This script is a simple hack from the Greasemonkey Script Compiler by: Arantius
If you encounter an issue with this version, please let me know. - only tested on windows and linux version of Firefox Mobile (Fennec)