I'm 89, and as far as I remember, I created the account within an hour or so of the announcement of the new account system.

autoconf has two purposes:

• Retargeting the installation and configuring options (eg --prefix, --with-*).
• Detection of the build environment (eg compiler, system calls, etc).

Converting from a plain Makefile to configure.in+Makefile.in is straightforward if your Makefile already uses variables for binaries and directories.

The main reason to use autoconf is the second point above; when you write code that uses system calls (eg read(2), write(2)) and not libc calls (eg fread(3C), fwrite(3C)), that differ between operating systems (eg BSD vs SysV vs POSIX), and need to detect which taste you have.

To answer your questions: autoconf is something I hook in when:

• the project is starting to get large,
• when I've been bit by operating system incompatibilities,
• or if I intend to release the code.