MEDIUM: lua: use the Lua-5.3 version of the library

The Lua-5.3 version of the library adds a required function to fix
a bug with the forced-yield system.

This patch permits to build with the Lua-5.3 library. Main changes
are:
 - "unsigned" type disappear to be replaced by signed type,
 - prototype of the yield function callback changes.
2 files changed