Install issue on apple silicon

I have an issue installing densvis (and the parent package scater) on M1 apple silicon.

It appears another user has an identical issue, so Id don't see the need to produce a working example.

https://stackoverflow.com/questions/35999874/mac-os-x-r-error-ld-warning-directory-not-found-for-option

Probably related to fortran, macOS, homerbrew etc.  