The interfaces that want to implement it can now add a callback on
libvlc::intf-boss.

 - use native MingW back-end on Windows, instead of kludges,
 - remove "base" pointer parameter,
 - inline.

It closes #5053.

It closes #4695.

It is send on vout count changes (close #5277).

 - only check for libv4l2 if V4L2 is supported,
 - only check for --enable-pvr if V4L2 is supported,
 - remove mostly useless --enable-libv4l2 and --enable-v4l2.

Save CFLAGS and CXXFLAGS after the compiler is detected, rather than
before. This is when autoconf sets -g and -O2 automatically by default.

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

Untested

macosx: replace the 'basic' vs 'all' radio button on the bottom left of the prefs window with a simple button, which is nicer and more 'Mac-like'

This way, the Linux code is run (without shader) and we achieve a working vout. Thanks a lot for the massive help by fenrir\!

It could be the reason people noticed difference between libmpeg2/avcodec encodes.
As mentioned in VDD'11.

Conflicts:

	extras/package/win32/vlc.win32.nsi.in
Signed-off-by: Christophe Mutricy <xtophe@chewa.net>