As noted by Prof. Ripley at: https://stat.ethz.ch/pipermail/r-sig-mac/2020-November/013789.html. This can be addressed by adding into ~/.R/Makevars :
r-makevars-mac
May 12, 2015 — The thing is then to get R to actually use this gcc compiler. After many hours of struggle, I got it working by modifying the “~/.R/Makevars” file, in .... Feb 19, 2017 — In late 2011, Martyn Plummer also wrote a helpful R Journal article on best practices ... this via DESCRIPTION and 127 CRAN package via src/Makevars . ... Also note that macOS / OS X has its own dependency chain due to ... 3925e8d270
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