Ruby

merge revision(s) 65ae2bb2e045aa8b668d3c30515f5a6cb3eb68ad: [Backport #18902]

    Thread#value: handle threads killed by a fork

    [Bug #18902]

    When a thread is killed because we forked, the `value` if left
    to `Qundef`. Returning it woudl crash the VM.
    ---
     test/ruby/test_thread.rb | 14 ++++++++++++++
     thread.c                 |  4 ++++
     2 files changed, 18 insertions(+)