func (w *Walker) export(pkg *apiPackage) {
	if verbose {
		log.Println(pkg)
	}
	pop := w.pushScope("pkg " + pkg.Path())
	w.current = pkg
	w.collectDeprecated()
	scope := pkg.Scope()
	for _, name := range scope.Names() {
		if token.IsExported(name) {
			w.emitObj(scope.Lookup(name))
		}
	}
	pop()
}

func set(items []string) map[string]bool {
	s := make(map[string]bool)