diff --git a/lib/rscons/monkey/string.rb b/lib/rscons/monkey/string.rb
index 7ef76f9..b17ebef 100644
--- a/lib/rscons/monkey/string.rb
+++ b/lib/rscons/monkey/string.rb
@@ -6,6 +6,7 @@ class String
   def has_suffix?(suffix)
     if suffix
       suffix = [suffix] if suffix.is_a?(String)
+      suffix = suffix.flatten
       suffix.find {|s| self.end_with?(s)}
     end
   end