* Update helpcontent2 from branch 'master'
  - Don't set LANG env var by accident
    
    ...as setting a GNU Make LANG var exports it to recipes as an env var, and see
    e.g. 56bc0b1a "Don't set locale env vars on
    macOS" for potential problems caused by that.
    
    This is the help half of a change spanning the core and help repos.
    
    Change-Id: Ib5faf612e9030db384f7408ecd4fd03e65120f17
    Reviewed-on: https://gerrit.libreoffice.org/70930
    Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>