Some of these checks before bitwise operations are redundant and compilers
do not always recognize them, so let's simplify the code to make the intentions
clearer.
The current check checks for n_sigbus_queue
being greater than or equal to SIGBUS_QUEUE_MAX,
when it should be just greater than as
n_sigbus_queue being SIGBUS_QUEUE_MAX indicates
that the queue is full, but not overflowed.
Rose