Autotools can be daunting if you plan to write code that’s portable to Ultrix, IRIX, Apollo’s UNIX whose name I forgot, NonStop, UNICOS, OpenVMS, z/OS, macOS, and modern Linux.

Nowadays we don’t bother supporting dozens of platforms. Even Windows is something we can push aside and suggest WSL if you really need to run it under Windows.

And I even try to make sure my code runs correctly on z/OS (which IS a UNIX).