Index: etc/mtree/BSD.include.dist
===================================================================
--- etc/mtree/BSD.include.dist
+++ etc/mtree/BSD.include.dist
@@ -228,6 +228,8 @@
         ..
         netdump
         ..
+        tcp_stacks
+        ..
     ..
     netinet6
     ..
Index: include/Makefile
===================================================================
--- include/Makefile
+++ include/Makefile
@@ -57,6 +57,7 @@
 	netgraph/atm netgraph/netflow \
 	netinet/cc \
 	netinet/netdump \
+	netinet/tcp_stacks \
 	security/audit \
 	security/mac_biba security/mac_bsdextended security/mac_lomac \
 	security/mac_mls security/mac_partition \