postgresql-7.4.6-2PGDG.src.rpm broken for Redhat 7,8 or 9

I have a standard Redhat 9 installation with the exception of upgrading bison to bison-1.875-7.1

I can build the postgres rpm files from the source for version 7.4.5 no problems with the following command:
rpmbuild --rebuild --define 'build89 1' --define 'python 0' --define 'test 0' --define 'plperl 0' --define 'tcldevel 0' --define 'pltcl 1' postgresql-7.4.5-2PGDG.src.rpm

However when I try the exact same on the 7.4.6 source rpm I get the following errors:

checking for zlib.h... yes
checking krb5.h usability... no
checking krb5.h presence... no
checking for krb5.h... no
configure: error: header file <krb5.h> is required for Kerberos 5
error: Bad exit status from /var/tmp/rpm-tmp.27397 (%build)

A quick comparison of the rpm spec file (postgresql-7.4.x-2PGDG.spec) reveals that the 7.4.5 version has the kerberos directory is set via:
%{?build7x:%define kerbdir /usr/kerberos}
%{?build89:%define kerbdir /usr/kerberos}

where as the 7.4.6 version has the kerberos directory is set via:
%{?build7x:%define kerbdir "/usr"}
%{?build89:%define kerbdir "/usr"}

I think you'll agree that this directory change is not the default for Redhat 7, 8 or 9

Regards
Donald Fraser