You can get the current sources to Lua as a gzipped tar file from

http://www.lua.org/download.html

It can be unzipped by !SparkFS. The directory thus obtained contains two files, Makefile and Readme, which you do not really need, and two directories doc and src. You might as well delete the file src.lua/hpp unless you intend to use C++ rather than plain C. You can change the filetype of src.Makefile to text as you will need to edit it. The source files have suffixes /c and /h. I am not quite sure which formats GCC will accept, but I change these filenames, stripping off the suffixes and placing them in directories c and h. Naturally I use a little RiscLua program for that, but you may well have other tools that can do this renaming.