This way, the official atomic functions will be used when available,
rather than VLC's own implementation.

This commit also enables proper atomic operations on some platforms
or with some toolchains. __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 is not
defined on some platforms such as ARM Linux, nor by other compilers
than GCC such as LLVM/clang. Then atomic operations wrongly fell
back to the lame mutex-based implementation.

This will break support for some old compilers and old or irrelevant
instruction set architectures. They would need to provide replacement
for the Intel-originated __sync_* builtin functions.

Since this constitutes mostly of macros and type definitions, it would
not fit too well in compat/. Most of the code would end up in
<vlc_fixups.h> rather than compat/. Moreover, I doubt that those
functions would be detected properly with AC_CHECK_FUNCS or
AC_REPLACE_FUNCS.

Anyway, VLC already has a separate header, and it will need to keep it
until <stdatomic.h> can be relied upon... many years from now.

This is now the same as was already implemented in the
set_relative_playlist_position_and_play() method.

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

macosx: improve the handling of broken prefs and make sure that the user is unable to re-break them without using the command-line or a text editor

This reverts commit 8bc285bd.

The original purpose for this code is fixed somewhere else today.

close #6769

In particular, V4L is (usually) an access_demux rather than an access.

Format the text. If it is identical and all parameters are unchanged,
there is no need to update - even if the format contains a $ sign.

A slave input should be used for audio, probably ALSA or Pulse.

Improve scene video filter to write pictures in a separate thread.

macosx: trust the user that s/he knows what s/he's doing when opening a VIDEO_TS folder (close #6108)

in other words, accept folders which aren't named 'VIDEO_TS'

It probably wouldn't hurt to provide helpers for mouse events.

This is similar to hotkeys. There is no need for a hand-over thread.

Thanks to Rémi for the help

If a thread can be cancelled, it can be joined.

Regression introduced in 55c6f688.

There is no matching vlc_object_alive() or vlc_object_waitpipe().