diff --git a/mrbgems/stdlib.gembox b/mrbgems/stdlib.gembox
index 72fb9e343..2b2f45334 100644
--- a/mrbgems/stdlib.gembox
+++ b/mrbgems/stdlib.gembox
@@ -51,4 +51,7 @@ MRuby::GemBox.new do |conf|
 
   # Use class/module extension
   conf.gem :core => "mruby-class-ext"
+
+  # Use errno extension
+  conf.gem :core => "mruby-errno"
 end