[This has already been reported as https://trac.macports.org/ticket/58717
but no solution was found yet. To have a broader discussion I'm also writing to this list.] [I'm using the current git version of both `macports-base' and `macports-port' on macOS 10.7.5; according to the recently posted instructions from Joshua I no longer have the lines cxx_stdlib libc++ default_compilers macports-clang-5.0 in my `macports.conf' file.] The `lilypond-devel' port can only be built with a non-ancient version of gcc; the Portfile comes with a blacklist to disable all incompatible compilers and a whitelist to enforce gcc. Since approx. two months there are problems with MacPorts – this is, the unmodified Portfile suddenly fails to work correctly. I only have `gcc8 @8.3.0_4' installed. After a successful build and installation, I get the message lilypond-devel is using libstdc++ (this installation is configured to use libc++) in the `rev-upgrade' phase, which triggers a re-build again and again until `port install' gives up. To me, this looks like a bug in `macports-base'... Werner