[luatex] Using libraries from luarocks

[Nils Pickert]

Hi all

I would like to use a library installed by Luarocks with LuaLaTeX (this
one:  https://github.com/minoki/luaexif )

As the wiki is currently not working for me and I am a complete Noob:
how do I do this?

LuaLateX does not find the library (because it seems to look in the
texmf paths for it...), so I linked the .so file in the same folder as
my main tex file.

It is then found, but complains "Symbol not found: _lua_isinteger"

My TeX File:
\documentclass{scrartcl}
\usepackage{luacode}
\begin{document}
Foo
\begin{luacode}
local exif = require("exif")
local data = exif.loadfile("DSCF0274.jpg")
\end{luacode}
\end{document}

I am using MacTeX 2018, which has luatex 1.07.0 (TeX Live 2018)
The library was installed with luarocks, luarocks itself from homebrew.

Thanks!
Nils