The new initializer and struct layout does not initialize the
__g_signals field in the old struct layout before the change in
commit c36fc50781 ("nptl: Remove
g_refs from condition variables"). Bring back fields at the end
of struct __pthread_cond_s, so that they are again zero-initialized.
Reviewed-by: Sam James <sam@gentoo.org>
(cherry picked from commit dbc5a50d12)