The jack_group2gid() function does a thread-safe lookup of a unix gid from a
unix group name.

The jack_promiscuous_perms() function adjusts the permissions of a shared
resource (socket, semaphore, shm segment, ...) referenced by a fd and/or a
path so it can be used by any member of the provided unix group.

By using those functions it will be possible to enable a secure promiscuous
mode. 'Secure' meaning here that one is not forced to launch every clients
with a (way) too permissive 0000 umask.

This wrapper driver has the same usage as its parent JackWaitThreadedDriver,
but for non-threaded (callback) drivers. After waiting for Initialize to
return, its main thread simply ends instead of calling the driver's Process
method in a loop. The decorated driver, which must extends JackRestarerDriver
instead of JackWaiterDriver, can restart the wait cycle by calling its
RestartWait method.