pthread_yield.3: ATTRIBUTES: Note function that is thread-safe

The function pthread_yield() is thread safe.

Signed-off-by: Peng Haitao <penght@cn.fujitsu.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
pthread_kill.3: ATTRIBUTES: Note function that is thread-safe

The function pthread_kill() is thread safe.

Signed-off-by: Peng Haitao <penght@cn.fujitsu.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
pthread_kill_other_threads_np.3: ATTRIBUTES: Note function that is thread-safe

The function pthread_kill_other_threads_np() is thread safe.

Signed-off-by: Peng Haitao <penght@cn.fujitsu.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
pthread_self.3: ATTRIBUTES: Note function that is thread-safe

The function pthread_self() is thread safe.

Signed-off-by: Peng Haitao <penght@cn.fujitsu.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>