upower needs to add $(use_enable introspection) to configure flags and >=dev-libs/gobject-introspection-0.6.7 into dependencies. And there's a new version 0.9.3 available.
Created attachment 231047 [details] upower-0.9.3.ebuild Updated ebuild to include introspection support.
+*upower-0.9.3-r1 (11 May 2010) + + 11 May 2010; Samuli Suominen <ssuominen@gentoo.org> + +upower-0.9.3-r1.ebuild, metadata.xml: + gobject-introspection support wrt #319105 by Priit Laes.