Please add the Omega patch to Valgrind ebuild with useflag. Reproducible: Always Steps to Reproduce: 1. Note the absence of the leakfinder. :-) Actual Results: I tried a manual build, got impatient quickly with the amount of fiddlery required to make it actually work (really odd build requirements, optimistic flag probs, etc, etc) and decided that the maintainer probably best look at it.
This is not something for Gentoo, it's for the upstream developers. If you want that feature in valgrind, ask them to include it.