--- rel/reltool.config.orig	2018-08-20 14:11:32 UTC
+++ rel/reltool.config
@@ -11,6 +11,7 @@
 % the License.
 
 {sys, [
+    {excl_lib, otp_root}, %% require erts runtime from FreeBSD ports
     {lib_dirs, ["../src"]},
     {rel, "couchdb", "3.1.1", [
         %% stdlib
