MKVToolNix 7.1.0 was released on 2014-07-27. Please add it to Portage.
Please also add this patch to fix compilation with boost-1.56.0: https://trac.bunkus.org/changeset/0c89ff941bfdd9f3378312f293a84f13cf3e2a96
(In reply to Lars Wendler (Polynomial-C) from comment #1) > Please also add this patch to fix compilation with boost-1.56.0: > > https://trac.bunkus.org/changeset/0c89ff941bfdd9f3378312f293a84f13cf3e2a96 In CVS. *mkvtoolnix-7.2.0 (14 Sep 2014) 14 Sep 2014; Steve Dibb <beandog@gentoo.org> +mkvtoolnix-7.2.0.ebuild: Version bump, bug 520376 7.2.0 contains the fix.