On this platform we seem to get lots of other signals
while waiting for SIGKILL to be delivered.

Solution: use sigsuspend(<all signals blocked>)



dbug/dbug.c:
  New function _db_suicide_() which does kill(myself, -9) and then waits forever.
include/my_dbug.h:
  Let DBUG_SUICE wait forever until the KILL signal is delivered, and process dies.