Gentoo's Bugzilla –
Attachment 616628 Details for
Bug 711102app-office/libreoffice-6.3.5.2 w/ app-text/poppler-0.86.0: pdfioutdev_gpl.cxx:567:64: error: base operand of ‘->’ has non-pointer type ‘const string’ {aka ‘const std::__cxx11::basic_string<char>’}