See Software recommendations category. Referring to my own answer there, I think these questions should only be on-topic in case the OP manages to narrow down the scope sufficiently. In case the question contains some sort of use-case/usage scenario and important requirements, it should be OK - otherwise, probably too broad.
What Python library can I use to connect to Postgres?
This could probably be made on-topic by narrowing down the question further, to whatever might be relevant. For example are commericial libs viable or does it have to be open source? How up to date does it need to be, any particular Python version etc etc.
What is a good build system? (ie. makefile, etc)
This is far too vague and would need to be expanded with far more details. The current policy https://software.codidact.com/help/on-topic "Best practices, as long as clear "best" criteria are provided."
What file format can I use for my configuration files?
"Configuration file" can mean pretty much anything, but other than that, this sounds like it would be perfectly on-topic given that it is narrowed down to a specific tool chain.
What is an IDE I can use for large and complex C++ projects?
Could also be on-topic if narrowed down. What exactly is "large and complex", what version control are you using & do you require it to be integrated in the IDE, do you use static analysers and other such tools, any particular build requirements etc etc.
The common theme here would be: as long as they are specific and not asking about subjective opinions, these questions are fine. So far we haven't categorically closed all tool recommendation questions like on Some Othersite, but questions asking for opinions have been poorly received. I think handling tool recommendation questions on case-by-case basis is a pretty sensible approach, even if that's not exactly the easiest policy to moderate.