Interface signals

[Bill Haneman <bill haneman sun com>]

Hi folks:

You may recall that you can't look up signals for interface types that
haven't got any live implementors yet.  However we need to do just this
in the at-spi code, when registering emission hooks for those signals.

Revisiting this issue, the workaround that i've been using, which is
calling the type init code:

GType t = ATK_TYPE_TEXT;

has stopped working.

Does anyone know why this is, and what the current workaround should
be?  For various reasons it is not feasible to instantiate an instance
of an implementing class since those classes are private and not know to
the emission hook listener.

-Bill