Close #3485

Signed-off-by: Christophe Mutricy <xtophe@videolan.org>

Signed-off-by: Christophe Mutricy <xtophe@videolan.org>

Use only pkg-config.
Fix sdl_image detection

But you need careful, if you compile without X and then run with an X-enabled PulseAudio, boom.

Closes: #3650

 It fixes 'on top' behaviour when going fullscreen (at least for linux), and
it avoid having a 'Untitled Window' in the taskbar when fullscreen.

It properly fixes #3526.

The maximum number of surfaces it will allow is now 128, but the actual value
used is configured by the core (around 20-30 when DR is used, a few otherwise).

All the operations are done from the command thread now

This should help watching mp4-videos (&fmt=18 and 22 or something like that)
from youtube. ffmpeg for fallback for windows. Not idea about OS X side.

contribs: added Google's libvpx patch for ffmpeg with a couple of compilation fixes for Mac OS X and added another patch for libvpx

Please note that updating pre1 to pre3 won't work because of this missing key *cough*

Mac OS X: added various missing file extensions to the supported-by-this-application-list (xa, m3u8, b4s, vlc, xm, amr, aob, dts, cdg, idx, oma, voc, vqf, mpeg1, mpeg2, mpeg4, mts, mid, mlp, webm, rar, rec, rmi, s3m, vro, tod, utf)

This should fix usage on windows.

This removes a dangerous vlc_object_find(PARENT) and potentially
invalids var_DelCallback().
It also avoids useless callback destructions and so fixes some dvd menus.

It will simplify improvements of vout_Request.

Don't use the iphone-trick, but instead parse the playlist-file and add
all the video-types on one run. Seems that when adding nodes on lua sd plugin,
theres some flickering.

It seems that decoders not using AVContext::get_buffer() do not
initialize AVFrame::reordered_opaque.

It basically works but they are some issues to be fixed.