|| ( >=dev-libs/json-c-0.11:= >=dev-libs/libfastjson-0.99.2:= ) Using := inside || () is disallowed and broken. Even if it weren't, the dependency would still be incorrect since the two libraries don't collide with each other and liblognorm prefers libfastjson over json-c. Two possible solutions are: 1. Add USE flag to toggle between the two, and ensure the flag status is respected (would require some hackery), 2. Just depend on libfastjson and ignore json-c. liblognorm is only used by rsyslog and sagan, and rsyslog requires libfastjson anyway.
commit c56db9177e78ad1abbb4a3476d552942f69eba0a Author: Michał Górny <mgorny@gentoo.org> AuthorDate: Tue Jun 21 21:53:00 2016 Commit: Michał Górny <mgorny@gentoo.org> CommitDate: Tue Jun 21 21:55:07 2016 dev-libs/liblognorm: Fix := in || and automagic dep on fastjson, #586312