So, a couple days ago I shared a Makefile with John, meant to become the standard Go project Makefile at CloudFlare. Here are the comments:

> John: This is very expensive. Can't it be calculated once (:=)?

> Me: The problem is that we don't want to calculate it if we don't need it, because we might run make before go is installed, and that would fail.

> John: http://blog.jgc.org/2016/07/lazy-gnu-make-variables.html

I think he wrote this piece to answer my question.

That's working with great people right there.