As I understand it, ebuilds should not consider kernel configs to be mandatory unless this is necessary for building the package itself. If there is a runtime dependency on a feature (in this case PPS, NETWORK_PHY_TIMESTAMPING and PTP_1588_CLOCK) these can be defined as advisory instead.
Proposed fix is in pull request commit: https://github.com/gentoo/gentoo/pull/11566/commits/ed84fc343d098bab030167d0dd1e9ff722a30c7e
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=e71ee81acf44dbf10d228da268024ce9873996be commit e71ee81acf44dbf10d228da268024ce9873996be Author: Thomas Beierlein <tomjbe@gentoo.org> AuthorDate: 2019-05-20 05:18:07 +0000 Commit: Thomas Beierlein <tomjbe@gentoo.org> CommitDate: 2019-05-20 05:18:07 +0000 net-misc/linuxptp: Make kernel config advisory Reported-by: Paul Steward <pstew@google.com> Closes: https://bugs.gentoo.org/685278 Closes: https://github.com/gentoo/gentoo/pull/11566 Package-Manager: Portage-2.3.66, Repoman-2.3.12 Signed-off-by: Thomas Beierlein <tomjbe@gentoo.org> net-misc/linuxptp/linuxptp-1.8.ebuild | 4 ++-- net-misc/linuxptp/linuxptp-2.0.ebuild | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)