Created attachment 887014 [details] dev-db/mysql-workbench-8.0.36 build.log (xz compressed) tr1 is an experimental modification of the c++ specification that gcc includes in its libstdc++ but llvm's libcxx doesn't. To my understanding experiment was superseded by C++11 which mysql-workbench is built with already. https://en.wikipedia.org/wiki/C%2B%2B_Technical_Report_1
Created attachment 887015 [details] emerge --info