Log Message:
devel: Add lua-compat53. Based on work by Jonathan Buschmann in wip.

This is a small module that aims to make it easier to write Lua
code in a Lua-5.3-style that runs on Lua 5.3, 5.2, and 5.1.

It does *not* make Lua 5.2 (or even 5.1) entirely compatible
with Lua 5.3, but it brings the API closer to that of Lua 5.3.