Thread: How to use strverscmp()?

I've read a little about a function to compare version numbers, strverscmp(), and I find a lot of information about it, but not how to use it.

Seems to be a ”GNU extension”, what does that mean?
What do I need to #include?
Is there anything I need to know when compiling (using gcc), such as -lSomething?

It seems to be installed on my system already; at least the man page is there.