for all devices.

This is required for example for some adaptive sample rate converters
which are executed on top of JACK. These SRCs are using the time stamp to
calculate the buffer fill level between playback application and sound
card.

Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>

Fixes #338

Adjusts the permissions of linux futexes when promiscuous mode is enabled.

Includes optimizations for internal clients, but not enabled yet.

Patch by Thomas Brand <tom@trellis.ch> and in accordance with jackd1
code base.

It is already defined by conf.define().

Call JackAlsaDriver::Close() when alsa_driver_new() fails, to
release devices acquired just before that call. Otherwise
JackAlsaDriver::Open() will never succeed again, as re-acquiring the
same device will fail with "A handler is already registered" DBus error.

The midi thread was always late after 2^31-1 Samples (~13.5h at 44.1kHz), because when there's no time limit, a uint64_t sample counter was compared against a signed 32bit INT_MAX to determine lateness. Now the CPU lockup will occur only after ~3 million years (at 192kHz), and because of the overflow it will presumably fix itself after a few milliseconds.

It's used for get_cycles() implementation, but it's never used.
On certain architectures it gives a warning which is be confusing.