problems setting HAVE_KRB_PRINCIPAL

[Per Boussard, ERA/T/ED]

It seems older versions of kth-krb don't have the struct krb_principal
typedeffed in krb.h, which makes the test in configure.in (annotated as a
'Gross hack..') not set HAVE_KRB_PRINCIPAL. I guess the appropriate way to
fix this would be to check for the version of kth-krb (or do another test
altogether). The problems that follow complain about ANAME_SZ, INST_SZ and
REALM_SZ not being defined (compiling koerror.o), so it's not trivial
(wasn't for me anyway) to understand the root of the problem.

I'll get current (no problem), but I guess the build will be friendlier if
this can be amended.

/Per
----
Per Boussard, KI/ERA/T/ED          Office: +46 8 404 55 11
UNIX System Administrator          Fax: +46 8 757 55 50
Ericsson Radio Systems AB          Home: +46 8 570 349 67
S-164 80 STOCKHOLM, SWEDEN         Email: Per.Boussard at era-t.ericsson.se