diff --git a/ext/hamlit/extconf.rb b/ext/hamlit/extconf.rb
index f0c98814..74153f9a 100644
--- a/ext/hamlit/extconf.rb
+++ b/ext/hamlit/extconf.rb
@@ -1,3 +1,4 @@
 require 'mkmf'
 
+$CFLAGS << ' -Wall -Wextra'
 create_makefile('hamlit/hamlit')