Ebuild for 18.15 attached. Seems to work for me. Reproducible: Always Steps to Reproduce: 1. emerge sci-libs/dlib Actual Results: Old dlib 18.7 emerging. Expected Results: New dlib 18.15 emerged.
Created attachment 403170 [details] Ebuild for dlib-18.15. Can be just put along with present ebuilds. Works for me.
+*dlib-18.15 (15 May 2015) + + 15 May 2015; Justin Lecher <jlec@gentoo.org> +dlib-18.15.ebuild, + -dlib-18.4.ebuild, dlib-18.7.ebuild, metadata.xml: + Version Bump, bug #549314; drop old +