add libhybris support
add libhybris support

it uses the Android fbdev HAL[1] (through libhybris[2])
and the libhybris implementation of wayland-egl.

Configure flags:
 cairo:
   --enable-glesv2=yes  --enable-egl=yes
 weston:
   --with-cairo-glesv2 --enable-fbdev-compositor
 hybris:
   --enable-wayland --enable-arch=x86
   --with-android-headers=<android-headers> --enable-alinker=jb

The android headers are extracted from an AOSP tree,
using hybris/utils/extract-headers.sh

[1]:
https://github.com/android/platform_hardware_libhardware/blob/master/include/hardware/fb.h

[2]: https://github.com/libhybris/libhybris

Signed-off-by: Adrian Negreanu <6275e895b07c55965e568461471033e41dc8e923@intel.com>

Fantu/compositor-spice,giucam/weston,udoprog/weston,krezovic/weston,mchalupa/weston,jonnylamb/weston,mchalupa/weston,sir-murray/weston,kwm81/weston,jonnylamb/weston,Tarnyko/weston-xdg_surface_present,udoprog/weston,krezovic/weston,kwm81/weston,sir-murray/weston,Fantu/compositor-spice,eyolfson/weston,xorgy/weston,Gnurou/weston,eyolfson/weston,xorgy/weston,Gnurou/weston,giucam/weston,Fantu/compositor-spice,Tarnyko/weston-xdg_surface_present