Lua devs released a few days ago a beta version of the upcoming 5.2
I tried to adapt the slackbuild.org build script
for the new version:
hope can be useful to play with it a little early: I seem to have spotted many Lua users here and, as you can read in the link above too, there are many changes from 5.1.x and some incompatibilities
EDIT: for the reasons above, if I were you, I won't use it to upgrade a 5.1.x package installed as a dependency of another package! Instead, can be handy for porting/testing lua code written for the new version.