I tested this with Heimdal Kerberos on a BSD system and one problem I found was that com_err.h doesn't exist in Heimdal.
I removed the #include and then tested it on Ubuntu 18.04.4 LTS and the code compiled fine there, so I'm going to guess that your code doesn't need com_err.h.
I tested this with Heimdal Kerberos on a BSD system and one problem I found was that com_err.h doesn't exist in Heimdal.
I removed the #include and then tested it on Ubuntu 18.04.4 LTS and the code compiled fine there, so I'm going to guess that your code doesn't need com_err.h.