What's new in at-spi2-core 2.9.90:

* Separate out X-dependent functionality, allow building without X11 (albeit
  with various things not working), and don't query/use X if DISPLAY is not
  set (BGO#682199, BGO#701378).

* Add atspi_text_get_string_at_offset, and deprecate
  atspi_text_get_text_at_offset.