Created attachment 464168 [details] build.log See the build log.
Could you add emerge --info too please?
Created attachment 464204 [details] emerge --info glibc
Added locale-gen as an empty patchset as: https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=6f49e6fc1120471c8f5f3ca9cdfe367c88a5d055 live ebuild will likely not be usable as-is as vanilla glibc tries to violate sandbox constraints which are patches by gentoo as: https://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo/src/patchsets/glibc/2.25/00_all_0001-disable-ldconfig-during-install.patch?revision=1.1&view=markup You might need to drop patches like that to /etc/portage/sys-libs/glibc-9999/ I'll try to address those upstream. Thanks for the report!