Copy some code from ejabberd's ejabberdctl.template

This code is copied from ejabberd's upstream ejabberdctl.template,
even if useless, to try to have a file as close as possible.

ecs/bin/ejabberdctl

@@ -150,6 +150,14 @@ exec_iex()
 # usage
 debugwarning()
 {
+    if [ "$OSTYPE" != "cygwin" ] && [ "$OSTYPE" != "win32" ] ; then
+        if [ "a$TERM" = "a" ] || [ "$TERM" = "dumb" ] ; then
+            echo "Terminal type not supported."
+            echo "You may have to set the TERM environment variable to fix this."
+            exit 8
+        fi
+    fi
+
     if [ "$EJABBERD_BYPASS_WARNINGS" != "true" ] ; then
         echo "--------------------------------------------------------------------"
         echo ""