[pandoc/f18] (2 commits) ...add bz reference for threaded rts issue (#862543)

[Jens Petersen]

Summary of changes:

  3bdd3fc... disable threaded runtime also to allow building on all seco (*)
  7320d47... add bz reference for threaded rts issue (#862543) (*)

(*) This commit already existed in another branch; no separate mail sent