This adds support for Sierra's new possibility to hide or move VLCs
status bar. It is synced with the VLC config setting.
Code also works if it gets compiled with a <10.12 SDK and it runs
on Sierra.

This fixes the overrun counter to always use the intended deadline
and interval values. Otherwise the counter value would be garbade, and
potentially cause an interger underflow. This would also potentially
corrupt the adjusted deadline and stall the timer thread.

This also fixes the disarm handling. From now on, a non-recurrent timer
is disarmed after expiration only if it has not been rescheduled or if
the new schedule is no later than the old one.

The timer interval is irrelevant if the deadline is zero, meaning
to disarm the timer.

refs #17142
fixes handling redirection of master playlist

Regression from 63337cab

This prevents undefined symbols in ELF shared libraries.

Approximately factor 2 faster.

Also adds build system support / cpu "detection" for arm64 neon.
Advanced SIMD (neon) is mandatory for general purpose ARMv8-a CPU so the
CPU feature detection is a constant 1.
Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

Avoids time gap of first AU.
First output pic dts/pts can't be from first seen NAL
if it has to go through sync on iframe.

Fixes weird stuff with muxers

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

and simplify sending data

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>