bpo-42972: _thread.RLock implements the GH protocol (GH-26734)


The _thread.RLock type now fully implement the GC protocol: add a
traverse function and the Py_TPFLAGS_HAVE_GC flag.
(cherry picked from commit 1cd3d859a49b047dd08abb6f44f0539564d3525a)

Co-authored-by: Victor Stinner <vstinner@python.org>
2 files changed