On 2018-5-31 15:39 , Ken Cunningham wrote: > gcc5 is using libstdc++ (this installation is configured to use libc++) > gcc6 is using libstdc++ (this installation is configured to use libc++) > gcc7 is using libstdc++ (this installation is configured to use libc++) Did cxx_stdlib_overridden.tcl not set these up right for you?