GObject-Introspection started warning for wrong annotations, and
StGenericAccessible::set-current-value has a return value annotation
even if it returns nothing. This generates the warning:
src/st/st-generic-accessible.c:146: Warning: St:
StGenericAccessible::set-current-value: invalid return annotation
Which, coupled with fatal warnings, breaks the Shell build.
Using the same idea that shell-generic-container. It implements
AtkValue with a dummy implementation based on signals. Javascript
code would connect to that and returns the proper value.
https://bugzilla.gnome.org/show_bug.cgi?id=648623