In order to make the game server build, I had to follow the author's instructions:
/* This program compiles for Sparc Solaris 2.6.
* To compile for Linux:
* 1) Comment out the #include <pthread.h> line.
* 2) Comment out the line that defines the variable newthread.
* 3) Comment out the two lines that run pthread_create().
* 4) Uncomment the line that runs accept_request().
* 5) Remove -lsocket from the Makefile.
*/
However, these instructions seemed to be out of date; there are not two occurances
of pthread_create, and the server does not work with these modifications.