I am attempting to build gnome-2.6_rc3 with emerge. The latest version of bonobo-activation in portage is 2.2.4, 2.4.0 is required.
bonobo-activation is since gnome 2.4 part of libbonobo, you shouldn't use or need a seperate bonobo-activation. gnome-2.6_rcx certainly doesn't depend on it.
Correction, bonobo-activation has been superceded by libbonobo. However, eog-2.6.0 needs this as a dependency (pkg-config). That is, pkg-config needs it in eog: bonobo-activation-2.0 >= 2.6.0 emerging libbonobo in before eog fixes this. No point in reopening, I'm sure you're aware of this.
oh was that causing it.. packagers of eog have been a bit too triggerhappy with the deps, there's actually no real need to have such a recent version. But i'll fix a workaround for it.