Created attachment 583132 [details] /tmp/sci-physics:root-6.18.00:20190716-192838.log.xz [100%] [34m[1mGenerating etc/allDict.cxx.pch[0m /usr/bin/cmake -E env ROOTIGNOREPREFIX=1 /usr/bin/python3.7 /tmp/portage/sci-physics/root-6.18.00/work/root-6.18.00/etc/dictpch/makepch.py etc/allDict.cxx.pch -I/tmp/portage/sci-physics/root-6.18.00/work/root-6.18.00_build/include ./bin/rootcling -rootbuild -1 -f allDict.cxx -noDictSelection -c -D__CLING__ -D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS -DROOT_PCH -fsigned-char -I./include -I./etc -I./etc/dictpch -I./etc/cling -I/usr/include -I/usr/include/freetype2 -march=x86-64 -mtune=k8 -mcx16 -msahf -msse3 --param l1-cache-size=64 --param l1-cache-line-size=64 --param l2-cache-size=512 -pipe -frecord-gcc-switches -std=c++11 -Wno-implicit-fallthrough -pipe -fsigned-char -pthread -DSYSTEM_TYPE_unix -I/tmp/portage/sci-physics/root-6.18.00/work/root-6.18.00_build/include etc/dictpch/allHeaders.h etc/dictpch/allLinkDefs.h error: unknown argument: '-msahf'
Created attachment 583134 [details] emerge-info.txt
There's also an upstream bug report: https://sft.its.cern.ch/jira/browse/ROOT-7639
I think this essentially duplicates: https://bugs.gentoo.org/show_bug.cgi?id=671810 (but for the newer release)
*** This bug has been marked as a duplicate of bug 671810 ***