Well, the config.m4 file is still a mess. Unfortenately there is no
libkadm55-dev debian package yet. So you have to have the krb5 sources
at hand and change config.m4 accordingly.

To successfully compile this extension under Debian you need the
following Kerberos packages:

libkrb5
libkrb5-dev
libkadm55

The missing of libkadm55-dev has already been reported to the libkadm55
maintainer: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=191616

If there are any questions or problems, feel free to contact me:

Holger Burbach <holger.burbach@gonicus.de>