otherwise the interface stays fullscreen when the video ends

  QML UI is injected from MainUI and Video integration is handled by the
  compositor

  Add KHRONOS_STATIC to allow static linking on Windows.

  QVoutWindow functionalities will be superseded by the compositor

  the variable points to the MainInterface and not its actual window

Without CONFIG_DEBUG set, libvpx is calling `$(STRIP) --strip-debug`
on the final library and removes the debug symbols from it. With the
variable set, it becomes a simple copy operation.

In addition, debug symbols should be enabled for all builds since we
strip in the end, so as to have the debug symbols in a separate file
when doing releases. In case we build with optimization, remove the
assertions.

MP4_BoxGet doesn't need a dedicated format for the given index.

The size of hashes are fixed so there is no need for str functions, as
otherwise strncpy complains about having the destination size equal to
the given size with fortify.

Size is an uint64_t because of vlc_stream_GetSize, not a size_t.

AudioUnit framework is not found on iOS and is not needed on MacOSX.

Remove AudioUnit framework as it is not found on iOS and only
AudioToolbox is needed.

In addition CoreServices cannot be linked for the iOS/tvOS targets as it
is available starting with iOS/tvOS 12.0+.

Fixes the following undefined references:

  "_OBJC_CLASS_$_NSNotificationCenter", referenced from:
      objc-class-ref in ios.o
  "_OBJC_CLASS_$_NSThread", referenced from:
      objc-class-ref in ios.o
  "_OBJC_CLASS_$_NSValue", referenced from:
      objc-class-ref in ios.o

There were no LDFLAGS for iOS/tvOS and vt_utils were not compiled but
linking worked because videotoolbox was linked in the final static
library archive.

Cocoa doesn't exist on iOS and tvOS.

Fixes 6746f578

You can't keep track of scheduled ES as they don't exist
and they expire with the command list.

you can't have assert() between priv/public spaces
if the enums can collide

fixes start case when min buffering < playlist duration

refs VLCKit/-/issues/374

The API is forbidden.

It could be done with this winrt API:
https://docs.microsoft.com/en-us/windows/uwp/launch-resume/launch-the-default-app-for-a-file

We may want to build for Win10/UWP via the command-line.

don't force compilation for Windows XP
don't call DebugBreak() (in debug builds)