Looking at Debian, they are distributing a series of patches to the Makefile. Getting away from autotools by having every distro patch your makefile might still be better than autotools, but I'd hope we might be able to do even better?
Where do you see that, sorry? I'm looking at the "Download Source Package" section here:
https://packages.debian.org/sid/stterm
...and the only patch on there is debian/patches/0001-fix-buffer-overflow-when-handling-long-composed-inpu.patch, which doesn't touch Makefie.
https://sources.debian.org/patches/suckless-tools/46-1/
Looking at Debian, they are distributing a series of patches to the Makefile. Getting away from autotools by having every distro patch your makefile might still be better than autotools, but I'd hope we might be able to do even better?