Not able to run stan due to compiler

Using macOS. When I install/update stan, I see that R is using clang++ to compile. I’ve updated my ~/.R/Makevars to CXX=g++-10 (install from homebrew) and when I run R CMD config CXX I see g+±10.

Any suggestions on how to fix this installation issue?

It looks like adding CXX14=g++-10 fixed this issue.