More like some obscure pre-c89 stuff. But it takes actual work and testing to get that working, so most people have a configure script that checks for all that stuff but when it's time to compile it only actually works on their specific Linux distro.

I have a vivid memory of autoconf. I set it up best as I could. Someone ran ./configure. It triggered a new run of autoconf that failed because of mismatching autoconf version. Why it triggered a new run? Because of mtime checks. Why did they say it needed to be rerun? Because git doesn't preserve mtime. I guess it's just assumed that everyone distributes their sources as a tarball. I spent many hours trying to figure out how to bypass those issues, and I can't remember if I ever succeeded.

These days I just use Rust instead.

autoconf's principal purpose is to waste time.