gl: check for X unconditionally

Without this the HAVE_X macro is empty, not "no" or "yes", which is not
what the later code is counting on.

https://bugzilla.gnome.org/show_bug.cgi?id=726591
gl: fix the use of always-defined macros

After 2a0f0399ae226089c2ba07b1b904741b856f37af GST_GL_* macros are always
defined to 0 or 1. Don't use #ifdef ... or #if defined() on them.

https://bugzilla.gnome.org/show_bug.cgi?id=726591
gl: don't default to GST_GL_HAVE_WINDOW_DISPMANX=1

Mistake introduced by 2a0f0399ae226089c2ba07b1b904741b856f37af

https://bugzilla.gnome.org/show_bug.cgi?id=726591
dvbsuboverlay: Don't forward text gap events downstream

That gap is only for the subtitle stream and not for the video stream.
gl: keep only one occurence of '#include <EGL/egl.h>'

To simply maintainance if we need to put specific includes around it.
gl: silence warnings building for RPI related to 'vcos_*'

Similar than 1190a79b199584cfc4dd62c474531c32cfbba425
gl: silence a critical if upstream does not provide us with meta params
gl/mixer: fix download check for failure
gl: use wglCreateContextAttribsARB to create share context

https://bugzilla.gnome.org/show_bug.cgi?id=726494
check: fix make check

The mpeg parser now flags the stream as mpeg2 if there is a picture
extension header, so remove it for mpeg1 data.
gl/win32: use the correct include and gst-indent
gl: reorganize the extension headers by function rather than api
gl: and update the Makefile
gl: fallback to glGetString if GL_NUM_EXTENSIONS fails

Need it on MacOSX 10.7.5
gl/upload: remove the legacy GL 1.x upload path

uploading requires shaders and fbos available in GL2.
gl: remove explicit reference to X_CFLAGS

They are in GL_CFLAGS if required
gl/upload: add support for the bt709 color matrix
gl/download: add support for the bt709 color matrix
gl: fix out-of-source builds.

Always use the locally generated <gst/gl/gstglconfig.h> file.

Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
codecparsers: h264: fix rbsp_more_data() implementation.

Account for trailing zero bits when checking for rbsp_more_data().

In particular, fix an hypothetical stream whereby rbsp_more_data()
is called in the following conditions for PPS header: NalReader
reached position 20, 12 bits are remaining and trailing data at
current byte position is c8 00.

rbsp_more_data() used to return TRUE whereas it should obviously
return FALSE because x8 00 represents a valid rbsp_trailing_bits()
structure.

https://bugzilla.gnome.org/show_bug.cgi?id=685890

Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>