- nodejs-symlink-deps: don't create an empty node_modules dir when a module
has no dependencies
- nodes-fixdep: support adding deps when none exist
- use libexecdir for RPM helper scripts (per packaging guidelines discussion)
- Add the full set of headers usually bundled with node as deps to nodejs-devel.
This way `npm install` for native modules that assume the stuff bundled with
node exists will usually "just work".
