This is an experimental overlay for building the Gentoo tree with BoringSSL instead of LibreSSL or OpenSSL!
NOTE: This will most likely never be supported by upstream, which explicitly says that BoringSSL should not be used as a system provider.
With paludis: see Paludis repository configuration
With layman:
layman -f -o https://raw.githubusercontent.com/lluixhi/gentoo-boringssl/master/boringssl-overlay.xml -a boringssl