diff --git a/Rsconscript b/Rsconscript
index d5e73aa..a81c4c5 100644
--- a/Rsconscript
+++ b/Rsconscript
@@ -26,7 +26,7 @@ MB = 1024 * 1024
 
 class HulkBinObj < Builder
   def run(options)
-    FileUtils.mkdir_p(File.dirname(@target))
+    @cache.mkdir_p(File.dirname(@target))
     File.write(@target, <<EOF)
 .section ".rodata"
 .balign 4096