Is there a rpmbuild that works on macosx? I am working on a maven build that needs to make an rpm.  Is there a native rpmbuild utility that will run on MacOSX?  So far I have found some old abandoned macports/darwin projects and people recommending running virtual box/parallels in virtual VM mode.  Is there really no native tool for building rpms on Mac?
Building RPMs or more specifically the binaries/libraries within them on a Mac is not a safe bet because you can run into a number of issues involving architecture mismatches, among other issues like library linking.

In short, if you're building for Linux, you really want to build on Linux. It's possible to cross-compile, but IMHO this is incredibly difficult on OS X.