Looks like ther is unofficial patch for kernel 3.10: https://code.google.com/p/easy-slow-down-manager/issues/detail?id=15 maybe it's worth it to apply to new -r1 ebuild
I addded an -r1 version to my overlay. http://www.startux.de/gitweb/quarks.git/commit/3e4c552508b020a98f336285d6fb2b6c040558c8
This bug should be closed. The patch has been added to the tree : > 19 Apr 2014; Devan Franchini <twitch153@gentoo.org> > +files/easy-slow-down-manager-0.3-kernel-3.10-1.patch, > easy-slow-down-manager-0.3.ebuild: > Adds patch to compile on systems with kernel-3.10.1 and up