Verify rstan installation failed (MacOS Catalina)

Hi, I installed command line tools following:
as closely as I could, having downloaded ‘Command Line Tools for Xcode 12’ from:
then I enabled compiler optimization and installed rstan from source following instructions in:

All seemed to be going well enough (passed the RcppArmadillo test from the coatless professor). But then, when I ran the verification commands (from from

example(stan_model,run.dontrun = TRUE)

R displayed:

stn_md> stancode <- ‘data {real y_mean;} parameters {real y;} model {y ~ normal(y_mean,1);}’

stn_md> mod <- stan_model(model_code = stancode, verbose = TRUE)

TRANSLATING MODEL ‘16a540c6086086816528e4524def24d9’ FROM Stan CODE TO C++ CODE NOW.
successful in parsing the Stan model ‘16a540c6086086816528e4524def24d9’.

and stood there showing me nothing else for more than 30 minutes. Finally, when I pressed Esc to interrupt the process, I got:

Warning messages:
1: In system(paste(CXX, ARGS), ignore.stdout = TRUE, ignore.stderr = TRUE) :
system call failed: Result too large
2: In system(paste(CXX, ARGS), ignore.stdout = TRUE, ignore.stderr = TRUE) :
error in running command

Anyone has any idea of what is going on? I am using R version R 4.0.3 GUI 1.73 Catalina build (7892) and macOS Catalina 10.15.7.

Thank you for any feedback and my apologies if I am repeating a question that I could not find in the archive.

If you are using R 4.x, it is best to delete the ~/.R/Makevars and ~/.Renviron files, install XCode, and then reinstall rstan.

Yes, I did that. Thanks!