diff --git a/mk-2nd.awk b/mk-2nd.awk
index 1f63763..4493bcf 100644
--- a/mk-2nd.awk
+++ b/mk-2nd.awk
@@ -1,6 +1,7 @@
-# $Id: mk-2nd.awk,v 1.19 2005/01/22 16:30:04 tom Exp $
+# $Id: mk-2nd.awk,v 1.23 2021/06/17 21:20:30 tom Exp $
 ##############################################################################
-# Copyright (c) 1998-2004,2005 Free Software Foundation, Inc.                #
+# Copyright 2020,2021 Thomas E. Dickey                                       #
+# Copyright 1998-2004,2005 Free Software Foundation, Inc.                    #
 #                                                                            #
 # Permission is hereby granted, free of charge, to any person obtaining a    #
 # copy of this software and associated documentation files (the "Software"), #
@@ -52,6 +53,13 @@
 #
 # Fields in src/modules past $3 are dependencies
 #
+function in_subset(value) {
+		value = " " value " ";
+		check = subset;
+		gsub("[+]", " ", check);
+		check = " " check " ";
+		return index(check,value);
+	}
 BEGIN	{
 		found = 0
 		using = 0
@@ -60,14 +68,14 @@
 		using = 0
 		if (subset == "none") {
 			using = 1
-		} else if (index(subset,$2) > 0) {
+		} else if (in_subset($2) > 0) {
 			if (using == 0) {
 				if (found == 0) {
 					print  ""
 					print  "# generated by mk-2nd.awk"
 					printf "#   model:      %s\n", model
 					printf "#   MODEL:      %s\n", MODEL
-					printf "#   echo:       %s\n", echo 
+					printf "#   echo:       %s\n", echo
 					printf "#   subset:     %s\n", subset
 					printf "#   crenames:   %s\n", crenames
 					printf "#   cxxrenames: %s\n", cxxrenames