ssh or kerberos library searching for default realm (but why?)

Scanario (heimdal 1.5.1 and ssh 5.7p1 with Simon's patches):

$ ./kinit [email protected]
... Password: xxxx

$ ./ssh -v -v -o GSSAPIKeyExchange=yes [email protected]
(...)
unable to find realm of host habadrom
(...)
=> exit

habadrom is my local machine. It does not need to be in any realm for
kerberos to be useful. I have a perfectly working ticket in the
ticket cache. Is it ssh or the heimdal libraries that think that
they need the local realm of the local computer? If I supply a
fake realm

$ cat > FAKE << EOF
[libdefaults]
default_realm=FAKE
EOF
$ KRB5_CONFIG=FAKE ./ssh -v -v -o GSSAPIKeyExchange=yes [email protected]

then it works, which proves that the knowledge of a real realm of
the local hostname is completely unneccessary. Do I now need to
ship a fake krb5.conf to cygwin users (whose computers typically
are not in some default realm at all)?

Harald.