There are a couple of things we can do to make our depends Makefile-based system more robust. A couple that have been in my head to potentially explore:

1. Some functionality that are not directly related to prerequisites producing targets could perhaps be simplified if delegated to scripts
2. Eliminating builtin rules and variables e.g. MAKEFLAGS += --no-builtin-variables: I've tried this, and it breaks libminiupnpc because it relies on builtin rules.
3. Require a recent-ish bash so that we can use set -euo pipefail and catch errors early

A lot of this is from: https://tech.davis-hansson.com/p/make/ (ignore the title)