as we'll need seekpoints for UI: chapters offsets were not sufficient.

This lifts the PATH_MAX characters limit, and should fix encoding on
POSIX non-UTF-8 systems.

Decoders are never "killed", so this had no effects.

(Same reasons as VLC_OBJECT_AOUT)

Audio output is not a descendent of input thread, so there was no real
use for this object type anymore.

macosx: make sure that we don't block media keys for iTunes in case the user doesn't want to use them within VLC

Changing this option requires a relaunch now, which is automatically offered when needed.

Fixes #5025

3gp4 is not compatible to isom, while 5, 6 and 7 should be
Ref #4979

This doesn't help users to report issues...

Without this, libvlc_media_parse() will deadlock on non-file items.

Also fix indentation (4 spaces)

This has no effects, so lets not do it.