diff --git a/ext/yajl/extconf.rb b/ext/yajl/extconf.rb
index 631c68c..fc9f4af 100644
--- a/ext/yajl/extconf.rb
+++ b/ext/yajl/extconf.rb
@@ -1,7 +1,7 @@
 require 'mkmf'
 require 'rbconfig'
 
-$CFLAGS << ' -Wall -funroll-loops -Wno-declaration-after-statement'
+append_cflags(%w[-Wall -funroll-loops -Wno-declaration-after-statement])
 $CFLAGS << ' -Werror-implicit-function-declaration -Wextra -O0 -ggdb3' if ENV['DEBUG']
 
 if ENV['SANITIZE']