diff --git a/lang/basic/src/maketokentab b/lang/basic/src/maketokentab
index 3c8b76f45..6ceee720d 100755
--- a/lang/basic/src/maketokentab
+++ b/lang/basic/src/maketokentab
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-ed -s Lpars.h <<'+'
+ed -s "${1:-Lpars.h}" <<'+'
 1d
 1,$s/# *define //
 1,$s/ ...$//