Rscons.clean() removes any directories it created if they are empty

lib/rscons/builders/object.rb

@@ -55,7 +55,7 @@ module Rscons
                    end
       command = env.build_command(env["#{com_prefix}COM"], vars)
       unless cache.up_to_date?(target, command, sources)
-        FileUtils.mkdir_p(File.dirname(target))
+        cache.mkdir_p(File.dirname(target))
         FileUtils.rm_f(target)
         return false unless env.execute("#{com_prefix} #{target}", command)
         deps = sources