[nodejs/f18] (4 commits) ...add %nodejs_sitearch macro

[T.C. Hollingsworth]

Summary of changes:

  3a234df... install development headers (*)
  48d6c59... need common.gypi too (*)
  658010d... forgot %{buildroot} (*)
  c3da87e... add %nodejs_sitearch macro (*)

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