diff --git a/tool/compile_prelude.rb b/tool/compile_prelude.rb
index 1f67d4c396..ddc1731ab2 100644
--- a/tool/compile_prelude.rb
+++ b/tool/compile_prelude.rb
@@ -1,4 +1,5 @@
-*preludes, outfile = *ARGV
+preludes = ARGV.dup
+outfile = preludes.pop
 
 C_ESC = {
   "\\" => "\\\\",