The following ebuilds are available for testing by end users and are currently keyword-masked. Add the following to your package.accept_keywords to test:
=sys-apps/portage-2.3.47 **
=sys-devel/gcc-7.3.1-r3 **
=sys-apps/corenetwork-1.6.4 **
=x11-drivers/xf86-video-intel-2.99.917_p20180609 **
Here is a quick review of changes in the above packages. Portage is a new version from Gentoo, which has passed all unit tests. Gcc-7.3.1-r3 is a much-improved ebuild from @Temptorsent which now enables SSP by default for improved security. Corenetwork-1.6.4 has some bug fixes that have accumulated in git, and the new xf86-video-intel is the latest from git and needs testing, particularly on newer intel hardware like Coffee Lake and Kaby Lake refresh -- and it always seems like google chrome has rendering issues, so be sure to test Chrome with this driver.
Please test these things and report back your experiences.