diff --git a/bin/mktestsuite b/bin/mktestsuite
index d8171f3928d0d3ef2ea302e5cb2a42917b4b8b38..9172bd773e648b4912a94e80cd19bb253b49efb0 100755
--- a/bin/mktestsuite
+++ b/bin/mktestsuite
@@ -166,5 +166,5 @@ test_equal(max($2,$1,$3), $3)
 EOF
 
 cat $1
-) | (shift ; $M4 "$@" )
+) | (shift ; $M4 "$@" - )