Bernard Li pushed a new version of gexec out in response to my inquiries on the mailing list, it includes the Ganglia switch.
I did some further code changes and was able to generate a tarball which builds fine without any modification, can you please try it on your system and see if it works? All you need to is run `rpmbuild -tb` against the tarball: http://therealms.org/oss/ganglia/gexec-0.3.8.1375.tar.gz
