root@gitlab:~# pg_createcluster 9.5 main --start -e "LATIN1"
Creating new cluster 9.5/main ...
  config /etc/postgresql/9.5/main
  data   /var/lib/postgresql/9.5/main
  locale en_US.UTF-8
initdb: encoding mismatch
The encoding you selected (LATIN1) and the encoding that the
selected locale uses (UTF8) do not match.  This would lead to
misbehavior in various character string processing functions.
Rerun initdb and either do not specify an encoding explicitly,
or choose a matching combination.
Error: initdb failed