Hello, 3.1.0 fails to build with db-4.8 because it simply doesn't check for this version.
Created attachment 204659 [details, diff] configure check for db-4.8
Sunrise is a user overlay. You can get commit access and fix this yourself. [1] [1] http://overlays.gentoo.org/proj/sunrise/wiki/HandyLinks irc.freenode.net #gentoo-sunrise