The following mask changes are necessary to proceed:
(see "package.unmask" in the portage(5) man page for more details)
# required by ccrtp (argument)
# /usr/portage/profiles/package.mask:
# Michał Górny <mgorny@gentoo.org> (2019-09-13)
# Unmaintained. No reverse dependencies.
# Removal in 30 days. Bug #694256.
=net-libs/ccrtp-2.1.2