We need to call XInitThreads before anyone tries XOpenDisplay or
something, and XInitThreads itself is not re-entrant, so call it before
we start LibVLC. This only "fixes" Xlib with VLC. Other LibVLC users
need to do something similar themselves. LibVLC cannot do it. Other
application may have already connected to X before it starts LibVLC.

 * gather all tests (that I could find)
 * X_FLAGS -> X_CFLAGS
 * test for Xlib.h only once
 * cleanup defaults (especially XvMC was silly)
 * factorize CPPFLAGS

Qt: now that you don't control the controls size anymore, be careful to resize the controller when buttons show up.

Close #2487.

(see http://forum.videolan.org/viewtopic.php?f=2&t=56224&p=186350)

Those were never used from plugins. This commit is a no-brainer.

This could crash the input thread(s).

This allows invoking debuggers directly from the command line again!

This allows using the http interface directly when builddir != srcdir.
This is needed to get rid of the ./vlc script.

According to ffmpeg/libavcodec/mpeg12enc.c:155 (rev:2fd06be07311)
profile and level must be inited at the same time, so, -1 will be
returned for mp2v with width > 720 or height > 576. But, if we leave
this fields blank (i.e. FF_PROFILE_UNKNOWN and FF_LEVEL_UNKNOWN) avcodec
will init them correctly.

This partially reverts commit b1b72b63.
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

This fixes the previous behaviour that was confusing.

Close partly #2237

Qt: cohenrency for volume between FSC and main Controller. Solve the 1% issue reported by Trax, close #1851.

We need to fix that better in post 1.0.0
Close #2377

Qt: remove the HACK with the static QAction for minimalViewAction, and fix a few minimalVIew issues.

 * add the possibility to go slower and faster (wasn't finished)
 * some cleaning and factorization