On 2008-11-03 version 3.0.0 was released. It would be nice to have the current version in the upstream portage repository.
Compiles nicely, but the only dep in tree (kpogre) fails quite nicely with the new version.
Renaming the ebuild and the gcc-patch file from the tree works for me. You need at least kpogre version 3.0.0. Renaming that ebuild, too.
+*libpqxx-3.0.2 (10 Sep 2009) + + 10 Sep 2009; Patrick Lauer <patrick@gentoo.org> +libpqxx-3.0.2.ebuild: + Bump to 3.0.2, fixes #265412. Yay, at last ;)