on all rhel-5 related conf file you should add this line: config_opts['macros']['%__arch_install_post'] = '%{nil}' since otherwise some build will fail on rhel-6 while building for rhel-5 since mock use the host's rpm and on rhel-5 it's nil while on rhel-6 it's /usr/lib/rpm/check-buildroot and since many rhel-5 packages buggy, thay won't compile in this way.
queued up for next release (1.1.10 and 1.0.17)
mock-1.1.10-1.fc15 has been submitted as an update for Fedora 15. https://admin.fedoraproject.org/updates/mock-1.1.10-1.fc15
mock-1.1.10-1.fc14 has been submitted as an update for Fedora 14. https://admin.fedoraproject.org/updates/mock-1.1.10-1.fc14
mock-1.0.17-1.el5 has been submitted as an update for Fedora EPEL 5. https://admin.fedoraproject.org/updates/mock-1.0.17-1.el5
mock-1.1.10-1.fc13 has been submitted as an update for Fedora 13. https://admin.fedoraproject.org/updates/mock-1.1.10-1.fc13
mock-1.1.10-1.el6 has been submitted as an update for Fedora EPEL 6. https://admin.fedoraproject.org/updates/mock-1.1.10-1.el6
Package mock-1.1.10-1.el6: * should fix your issue, * was pushed to the Fedora EPEL 6 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=epel-testing mock-1.1.10-1.el6' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/mock-1.1.10-1.el6 then log in and leave karma (feedback).
mock-1.1.10-1.fc15 has been pushed to the Fedora 15 stable repository. If problems still persist, please make note of it in this bug report.
mock-1.1.10-1.fc14 has been pushed to the Fedora 14 stable repository. If problems still persist, please make note of it in this bug report.
mock-1.1.10-1.fc13 has been pushed to the Fedora 13 stable repository. If problems still persist, please make note of it in this bug report.
mock-1.0.17-1.el5 has been pushed to the Fedora EPEL 5 stable repository. If problems still persist, please make note of it in this bug report.
mock-1.1.10-1.el6 has been pushed to the Fedora EPEL 6 stable repository. If problems still persist, please make note of it in this bug report.