kinit --help shows that the command has more options than what the man page describes. Missing from the man page:
-C id, --pk-user=ididentifier
-D directory, --x509-anchors=directory
I suggest adding them with the descriptions displayed by --help, ideally with more verbose descriptions though. Sorry for not having attached a patch, directly, I'm not too familiar with kerberos at the moment to be able to make sense of some of the options.