gtar*: update to 1.34

version 1.34 - Sergey Poznyakoff, 2021-02-13

* Fix extraction over pipe (savannah bug #60002)

* Fix memory leak in read_header (savannah bug #59897)

* Fix extraction when . and .. are unreadable

See https://lists.gnu.org/archive/html/bug-tar/2021-01/msg00012.html

* Gracefully handle duplicate symlinks when extracting

See https://lists.gnu.org/archive/html/bug-tar/2021-01/msg00026.html

* Re-initialize supplementary groups when switching to user privileges

(wiz)