xbmc: Add X.org/OpenGL support

xbmc: Add X.org/OpenGL support

- on ARM xbmc only supports EGL/GLES
  https://github.com/xbmc/xbmc/blob/Gotham/configure.in#L695
- rsxs depends on OpenGL
  https://github.com/xbmc/xbmc/blob/Gotham/configure.in#L1469
  so include a compile fix, courtesy of
  https://github.com/OpenELEC/OpenELEC.tv/blob/master/packages/mediacenter/xbmc/package.mk#L109

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>