diff --git a/ext/liquid/extconf.rb b/ext/liquid/extconf.rb
index 07dddfd6..824777e5 100644
--- a/ext/liquid/extconf.rb
+++ b/ext/liquid/extconf.rb
@@ -1,2 +1,3 @@
 require 'mkmf'
+$CFLAGS << ' -Wall'
 create_makefile("liquid/liquid")