necessary to build for all platforms?

Hi devs, Watching the files being compiled slowly scrolling by, as I too often do, led me to this question: Is there a reason that my machine (an x86-based Mac) is building modules in the SPARC or PPC directory? These absolutely need to be compiled when validating on any machine, but if I'm on the devel2 build settings, I don't see the need. Am I right that these aren't needed for debugging? If I am, is it reasonable to try to teach the build scripts how to avoid doing this? Thanks! Richard