I have a mostly-stable amd64 system, that I was trying to compile GTK+ 3 on for some development. After keywording the necessary packages, GTK+ failed to configure with an error about a missing cairo-gobject library. This library was available in cairo from 1.10.0 (well, 1.9.15) and is required for building GTK+ 3: http://lists.freedesktop.org/archives/cairo/2010-August/020418.html http://cgit.freedesktop.org/cairo/commit/?id=661f4859cdbc0394ed0a9db34ced0f4e2bbe78ff http://git.gnome.org/browse/gtk+/commit/?id=39b376681c8b99cf7031c0c4afb275f10cfaa167 As can be seen from the commit diff, the dependency of gobject in cairo is automagic. My install on this system was new enough that cairo had been compiled before glib, and therefore cairo-gobject was not present. I would suggest adding a ‘gobject’ USE flag to cairo, and making x11-libs/gtk+:3 depend on that flag. Also, the mail linked above suggests that gobject-introspection support could be added to cairo during the stable cycle, so it might be something to watch carefully for, as I guess it will involve some further changes.
I don't think a gobject USE-flag is needed. Almost no one uses cairo without glib installed, so it should probably be made a hard-dependency. Introspection support for cairo is currently shipped with dev-libs/gobject-introspection itself. That may move into cairo itself later, though.
Fixed in main tree. Thanks for report.
