Common targets are:
- meta-agl layer:
  * agl-image-boot                (just enough to boot)
  * agl-image-minimal             (minimal filesystem with APIs)
  * agl-image-minimal-crosssdk    (crosssdk for above)
  * agl-image-weston              (minimal filesystem with weston)
  * agl-image-compositor          (minimal filesystem with AGL compositor)
