[dovecot/core] 16bb1a: lib: add separator also if arr[0] is empty in stri...

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/dovecot/core
  Commit: 16bb1ac73aed6e30be610a2dc4eb9d1719f28559
      https://github.com/dovecot/core/commit/16bb1ac73aed6e30be610a2dc4eb9d1719f28559
  Author: Martti Rannanjärvi <martti.rannanjarvi at dovecot.fi>
  Date:   2016-12-27 (Tue, 27 Dec 2016)

  Changed paths:
    M src/lib/strfuncs.c
    M src/lib/test-strfuncs.c

  Log Message:
  -----------
  lib: add separator also if arr[0] is empty in string array joins

Also add a couple test cases.