LibVLC accept only "%u/%u" as AR.

The updatePlayerLayout boolean was not enough, specially since we know
inside the updateVideoSurfaces() function if we are using OpenGL or
MediaCodec rendering.

This doesn't seem to fix anything but this will trigger less round trip
between VLC and video size callbacks.

Macro magic but much more convenient to add methods and classes
since you only need to add it in one place now (jni_bindings.h).

The compile-libvlc.sh script will generate a shared library called
libvlc.so including libvlc, libvlccore, the plugins and the contribs.
Expose a pkg-config file per arch folder to be able to supply this to
other buildsystem like meson, cmake or autoconf.

Allow extending CFLAGS and LIBS, so that we can specify flags for libvlc
when generating its pc file.

The echo line and the next one were stitched without separators, so it
was displaying a path as file$path instead of, now, file: $path.

In order to generate the pkg-config file for libvlc, we want to be able
to specify the usual prefix/libdir/includedir variables.

Bash redirection allows writing the file using multiple commands without
repeating the file name again, and it will allow writing conditionals
for the output of the pc file.

There was no indentation despite the braces.

Update parse flags after their update in libvlc_media_parse_flag_t in
commit a82b09761535b2db5a0695b57c43ea12e51ad695

And not vlc-android build script that will use libvlcjni on a fixed
HASH...

In order to get NDKv25

And don't change the directory since this script can be sourced.

It is now possible to use this script for

- Build an existing VLC:
vlc $ ../libvlcjni/buildsystem/compile-libvlc.sh -a arm

- Build VLC from libvlcjni
libvlcjni $ ./buildsystem/compile-libvlc.sh -a arm

- Build VLC from vlc-android

This is needed as vlc-android's CI uses this project to compile the aar for Maven.
Therefore, vlc-android's publish.gradle file is not accessiible from it with the new
libvlcjni architecture.

Test that LibVLC can load.

To allow standalone libvlcjni gradle build.

It was only working when libvlcjni was used via vlc-android.

Use the standard layout.
This pave the way to add a androidTest folder (that does not seems to
work without this layout).

Contains last audiotrack timing improvements and RTSP deadlock fix.