sys-devel/gettext-0.15-r1 installs /usr/share/doc/gettext/examples/ as well as /usr/share/doc/gettext-0.15-r1. There is --docdir configure option. Using this and taking out the sed'ing in the ebuild works with a bit of rework of the dohtml. Patch attached.
Created attachment 101751 [details, diff] gettext-0.15-r1-doc.patch
in portage, thanks !