Ah the sound of silence...

The heimdal guys invented their own function header doc format, which is close enough to doxygen to be parsed by it, and far enough away to generate literally 100s of warning messages
Don't add 'no' to cflags when libkrb5 is not threadsafe
Better error handling for heimdal

Apparently they don't use the comm_err API so all the messages come out as unknown...