When I try to compile R packages from source, it uses the compilers and settings defined in etc/Makeconf within the R installation directory. How can I override these settings?
I have an ~/.R/Makevars file (suggested e.g. here), and I included the settings I want there, but these are not being used for some reason. Why not, and how can I fix this?
I could not find the official documentation on ~/.R/Makevars and Makeconf—links would be welcome.
In the past, this very same setup used to work correctly for me, but recently it doesn't. I assume something must have changed in recent R versions, but I am not sure when. Were there any recent changes that could have affected this?
Motivation and context:
I am on macOS and I want to use gfortran from MacPorts. Thus I set FC = /opt/local/bin/gfortran-mp-11 and FLIBS = -L/opt/local/lib/gcc11 -lgfortran -lquadmath -lm in ~/.R/Makevars. However, the system still wants to use a gfortran installation in /usr/local, which does not exist on my machine. It clearly takes the paths and options from etc/Makeconf. I am using the official R binaries.