Auto-sync with upstream branch master,
commit 6bbfc5c09fc5b5e3d4a0cddbbd4e2e457767dae7.
- Add statx conditionals for wordsize-32 *xstat.c
- regex: fix storage-exhaustion error (swbz#18040)
- regex: fix heap-use-after-free error (swbz#18040)
- manual: Document thread/task IDs for Linux