Remove variables that were never used, especially in tree_update structure

limit rebuilding the playlist control only when the notified item is
 expected to be visible. This improves responsiveness when playlists
are very large.

On a normal Win32 released build, we aren't going to ship the BCM dll
or ask our users to install the good version of the dll at the right
place and recompute the plugins cache...
Therefore, we need to open the dll and resolve the symbols.

ML holds some PL resources

libvlccore must not refer to .cpp files.

The mux was not passed in the chain.
This is a regression in f01fe561.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

This will be useful for RTSP.

For use within already variadic functions

pointed out by courmish

  - remove the awkward global lock and serializer mechanism
  - adapt to latest module API (fix compil errors)
  - be more specific about hwnd or xid depending on port
  - set display.x11 on Linux port