gcc whatever.c -L/usr/local/lib -lstevens
You can download libstevens.a to install on your own system.
You can add to (or create) environment variable in your .profile:
so that the /usr/local/lib is automatically searched for library files. Then you don't have to have the -L/usr/local/lib in the gcc command line.
Here's (581K) the tar file with all the examples' source code. Download onto your system, then:
tar -xf stevens.tarwill unbundle it. It'll make a apue/ directory and everything will be in it. Sourcefiles file tells where the chapter and section examples are.