proper way to distinguish epel from fedora

hi, what's the proper way to distinguish epel from fedora in the spec file? i'd like to add ExcludeArch: ppc ppc64 on epel but not in case of fedora in a package (since there is no java on ppc on epel). but what's the current recommended way to do so? unfortunately %{?rhel} is not defined even in rhel-5 so what else can i use to distinguish it from fedora? thanks in advance. ps. anyway it'd be useful to put into the epel packaging guidelines. -- Levente "Si vis pacem para bellum!"