[db48x]

It's not just about libraries.

Autoconf for example can abstract across different compilers from different vendors, with all their various incompatible command–line arguments. And it does that for a dozen or so different languages, not just C.

It can abstract across different function signatures in the libraries you're using. For example if you're calling a libc function where the arguments have changed, you can detect which version of the function you have and make your code work with either one.

It can do the same for structs and types as well.

It can test for system services, such as X Windows or the ability to run Perl scripts.

It can abstract over the differences between different implementations of common utility commands such as awk, grep, install, mkdir, and so on.

It does a lot of stuff!

[enriquto]

> It does a lot of stuff!

Of course it does. My point was that I've never found it did anything that I was interested in.

[db48x]

Then it wasn't written for you. It was written for people who want to distribute software to users who do not all run the same Unix operating system (not to mention the radically incompatible hardware of the day), and whose Unix vendors are all mutually hostile to any form of cooperation with each other. If all you ever install your software on is Ubuntu running in a VM at your cloud provider, then of course this will all be irrelevant to you.