Despite the fact that the git sources for gcc9 show a revision change to 2 in order to rebuild against the newer isl package, the current package built for darwin18 doesn't seem to be built that way. I get...
% sudo port install gcc9 ---> Computing dependencies for gcc9 ---> Fetching archive for gcc9 ---> Attempting to fetch gcc9-9.2.0_2.darwin_19.x86_64.tbz2 from https://packages.macports.org/gcc9 ---> Attempting to fetch gcc9-9.2.0_2.darwin_19.x86_64.tbz2.rmd160 from https://packages.macports.org/gcc9 ---> Installing gcc9 @9.2.0_2 ---> Activating gcc9 @9.2.0_2 ---> Cleaning gcc9 ---> Scanning binaries for linking errors ---> Found 6 broken files, matching files to ports ---> Found 1 broken port, determining rebuild order You can always run 'port rev-upgrade' again to fix errors. The following ports will be rebuilt: gcc9 @9.2.0 Continue? [Y/n]:
