LÖVE

I want to use the engine for some automation processes, but at some point I need to simulate a mouse click outside of the program window. I work on Windows and I really don't care if it will work on other platforms.

it's possible if you mess with the windows libs through ffi, but i don't have the exact knowledge what you'd need to load in (if anything) and what you'd need to define and call.

Edit: This might be helpful:
https://stackoverflow.com/questions/516 ... -from-code

Not what you asked for but depending on what you aim to do maybe an alternative - https://www.autoitscript.com/site/

Years ago I used it for a simple automation task, I can't even remember what it was, but I know it worked quite well and was easy to use. If you need the rest of Löve too it's of course of no help.