libglu: new package

This package is needed for OpenGL support in xbmc:
https://github.com/xbmc/xbmc/blob/Gotham/configure.in#L1070



Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>