https://github.com/mixxxdj/mixxx/commit/5d8002eddf58c192d806b349fdd0ce40388077f4 "Check via CMake whether the MS-GSL headers are installed" Configure phase works with dev-cpp/ms-gsl-4.0.0 . media-sound/mixxx/mixxx-9999.ebuild: RDEPEND=" + dev-cpp/ms-gsl
https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=6fbc5cc1417e81883b69988a0fc409f2966a031b "media-sound/mixxx: Update buildtime deps"