On Mac OS X 10.3.2 with developer tools installed,
I was able to get samba 3.0.2 to compile.
In order to do that, only two adjustments were
- adding the cups headers to /usr/include/cups/
- commenting out the contents of the function
krb5_locate_kdc in clikrb5.c (which should be ok)

The final problem with the build is one link error:
Linking bin/smbd
ld: Undefined symbols:

This symbol shows up in libads/sasl.o and in
libsmb/clikrb5.o as:
(undefined [lazy bound]) external _krb5_set_default_tgs_ktypes

How does one fix this?