diff --git a/util/mk1mf.pl b/util/mk1mf.pl
index 1f8b839e4..866629fe2 100755
--- a/util/mk1mf.pl
+++ b/util/mk1mf.pl
@@ -101,7 +101,7 @@ $out_def="out";
 $inc_def="outinc";
 $tmp_def="tmp";
 
-$mkdir="mkdir";
+$mkdir="-mkdir";
 
 ($ssl,$crypto)=("ssl","crypto");
 $ranlib="echo ranlib";