The adddepend script is missing and should be in postgresql-contrib: $ rpm -ql postgresql-contrib|grep adddepend /usr/share/doc/postgresql-contrib-7.4.8/README.adddepend
The reason it's not there is that contrib/adddepend has no Makefile to install itself. Given that the PG project plan is to remove that module from contrib, I don't think it's worth modifying the RPM packaging to special-case this.