fix for Lua 5.3 built without number / string conversion
fix for Lua 5.3 built without number / string conversion

This kind of Lua could be built with this command:
```
    hererocks --lua 5.3 --cflags="-DLUA_NOCVTN2S -DLUA_NOCVTS2N"
```
diegonehab/LuaSocket,diegonehab/LuaSocket,cjtallman/luasocket,diegonehab/LuaSocket,cjtallman/luasocket,cjtallman/luasocket,cjtallman/luasocket