Dolphin-9999 fails during compile phase due to missing package: net-libs/mbedtls. This package needs to be installed prior to installing Dolphin-9999 for successful Dolphin installation. Please reference the following for more info: https://forums.gentoo.org/viewtopic-p-7851650.html#7851650
The ebuild has been updated to reflect this new change. Thank you for submitting the bug report.