[nodejs-boom/f18] (3 commits) ...restrict to compatible arches

[T.C. Hollingsworth]

Summary of changes:

  4ff1b4c... add macro for EPEL6 dependency generation (*)
  de36812... invoke EPEL dependency generator macro conditionally to mak (*)
  e2b84a4... restrict to compatible arches (*)

(*) This commit already existed in another branch; no separate mail sent