Stress number of pending signals

[cirocosta]

to get over this:

   RLIMIT_SIGPENDING (since Linux 2.6.8)
          Specifies  the limit on the number of signals that may be queued for the real user ID of the calling process.  Both standard and real-time signals are counted for the purpose
          of checking this limit.  However, the limit is enforced only for sigqueue(3); it is always possible to use kill(2) to queue one instance of any of the signals  that  are  not
          already queued to the process.