Opam and gcc update

This is probably easy to solve but I can’t seem to do find out how. I’m on Mac OS 10.14, and as a byproduct of some homebrew upgrade, I have upgraded from gcc 7 to gcc 8.

Now it seems I can’t install gsl-ocaml anymore; installation fails with ld: file not found: /usr/local/opt/gcc/lib/gcc/7/libgfortran.4.dylib for architecture x86_64 which is understandable since gcc 7 is not there anymore.

I tried reinstalling gsl via homebrew and opam uninstall --force gsl but that didn’t help!? I can’t imagine I have to reinstall my entire opam switch?

Ok, solved. I had configured gsl-ocaml to use openblas. Turns out I had to reinstall openblas via homebrew to relink it correctly. This seems to be a problem of dependency handling in homebrew. Not opam related.