Log Message:
Update lang/lua52 to version 5.2.4.

Lua 5.2.4 fixes all bugs listed in
http://www.lua.org/bugs.html#5.2.3 [*]
and is now the current release of Lua 5.2.

Like all minor releases, this is strictly a bug-fix release;
no new features or improvements have been added.

[*] http://www.lua.org/bugs.html#5.2.3
1. Compiler can optimize away overflow check in table.unpack.
2. Ephemeron table can wrongly collect entry with strong key.
3. Chunk with too many lines may crash Lua.