Merge pull request #691 from masuidrive/fixed_build_dependency

Fixed build dependency

tasks/rules.rake

@@ -1,5 +1,5 @@
 def get_dependencies(file)
-  file = file.pathmap('%n.d') unless File.extname(file) == '.d'
+  file = file.ext('d') unless File.extname(file) == '.d'
   if File.exists?(file)
     File.read(file).gsub("\\\n ", "").scan(/^\S+:\s+(.+)$/).flatten.map {|s| s.split(' ') }.flatten
   else