diff --git a/ext/cld/extconf.rb b/ext/cld/extconf.rb
index 4b1c97c..8500a27 100644
--- a/ext/cld/extconf.rb
+++ b/ext/cld/extconf.rb
@@ -1,4 +1,4 @@
 #require 'mkmf'
 #create_makefile('cld/cld')
 
-system "./configure --prefix=#{Dir.pwd}"
+system "./configure --prefix=#{Dir.pwd}" unless File.exists?('Makefile')