qemu: Add an option to remove host sdl/gl checking
Add an PACKAGECONFIG in qemu to disable GL acceleration:
* By default configure try best to enable GL acceleration and fail when missing
host dependency(libSDL and libGL).
* End user can also choose to turn off GL capability, thus remove the host
dependence in building.
[YOCTO #2407] got fixed.
Signed-off-by: Zhai Edwin <edwin.zhai@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
