Seems from that page that;
Use the 32-bit x86-native tools to build 32-bit x86 code.
Is the one you need. So one would start a shell, execute that batch file, and right after (in the same shell) execute the LuaRocks command.
Since version 3 LuaRocks change its detection iirc. So maybe you’d have to install LuaRocks first from that prompt, too make sure it detects that same compiler during its set up.