Looks like this is it:

https://github.com/ttaylorr/dotfiles/blob/work-gh/Makefile

Yuck. What's the point of a Makefile if every single rule is phony?

i use a bash script not a makefile, but it's (mostly) idempotent:

https://gist.github.com/talentdeficit/253fd1eaf25cb41e5c24a4...