As noted in Bug 137665 gecko-sdk will be (soon) removed from tree and apps should port it to seamonkey/firefox Currently 1.4.2-r2 version in tree, has already added support for it, the overlay version has to be updated.
Created attachment 92309 [details, diff] gentoo-exp-totem-ff-backport.patch This patch is against gnome-experimental SVN.
Forgot to add, that only tested against firefox. Anyone using seamonkey? :)
Test 1.5.91