There is no change required for this update. One can simply copy the 0.99.12 ebuild to a new 0.99.16 ebuild. gtktalog hasn't been updated in a while and although the version number difference seems minor, 0.99.16 includes many bug fixes and even some major improvements since 0.99.12.
Created attachment 385 [details, diff] gtktalog-0.99.12-0.99.16.patch Nothing new... just an update to the copyright string.
Thanks for the update.