OK, very little about ebuild - it needs gnome2_icon_cache_update (and perhaps two keepdir lines, as on reemerge it removes /usr/share/ibus/icons and /usr/share/ibus/engine - unless those dirs aren't needed). More about something else. I took a look on client/x11/main.c, to see if something can be done about that _FORTIFY_SOURCE related warning. That code needs a lot cleanup work, IMHO. But anyway, I think I created a patch that looks correct to me (if somebody sees a bug in it, feel free to correct me). Should be upstreamed.
Created attachment 207446 [details, diff] fixes _FORTIFY_SOURCE warning That define in the source is probably a typo and it makes sense only if defined before other inclusions. (probably that 'exit' in main() should actually be 'return', but decided not to touch it)
1.2.0.20091014-r1 in cvs. Could you report _FORTIFY_SOURCE warning to upstream?