diff --git a/util/mkstack.pl b/util/mkstack.pl
index f708610a7..a86d91f67 100755
--- a/util/mkstack.pl
+++ b/util/mkstack.pl
@@ -97,7 +97,7 @@ while(<IN>) {
 EOF
 	}
 
-	foreach $type_thing (sort @sstacklst) {
+    foreach $type_thing (sort { $a->[0] cmp $b->[0]} @sstacklst) {
 	    my $t1 = $type_thing->[0];
 	    my $t2 = $type_thing->[1];
 	    $new_stackfile .= <<EOF;