app-text/texlive-core-2017-r3 has <app-text/poppler-0.64.0 in COMMON_DEPEND, but this is not needed as far as I can tell. texlive-core builds/runs just fine with poppler-0.64 for me. Reproducible: Always
app-text/texlive-core-2017-r4 was just added to the tree, and this is working for me too. bug 655052
app-text/texlive-core-2017-r4 also works with app-text/poppler-0.65.0, so this blocker is a bit outdated ...