Mask signals in iv_signal signal handler to prevent deadlock.
Mask signals in iv_signal signal handler to prevent deadlock.

While we are processing a signal (and have sig_interests_lock held),
a different signal can come in and preempt the signal handler, leading
to a deadlock on sig_interests_lock.  Solve this by masking all signals
for the duration of the signal handler.

Signed-off-by: Lennert Buytenhek <8858498612e3a522354216649776e3032dcb7e5b@wantstofly.org>

buytenh/ivykis,buytenh/ivykis