[R-SIG-Mac] clang: error: unsupported option '-fopenmp'

[Spencer Graves]

Hello, All:


       I'm getting "clang: error: unsupported option '-fopenmp'" when 
trying to build "https://github.com/helske/bssm" under macOS 10.14.14 
with R 3.6.0;  see below.


       What do you suggest?


       Thanks,
       Spencer Graves


p.s.  Helske told me he thought my compiler was out of date. However, 
I've so far been unable to find instructions that are sufficiently 
current to convince me I might not do more harm than good following them.


> R CMD build bssm
* checking for file ‘bssm/DESCRIPTION’ ... OK
* preparing ‘bssm’:
* checking DESCRIPTION meta-information ... OK
* cleaning src
* installing the package to build vignettes
       -----------------------------------
* installing *source* package ‘bssm’ ...
** using staged installation
** libs
clang++ -std=gnu++11 
-I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG 
-I"/Library/Frameworks/R.framework/Versions/3.6/Resources/library/BH/include" 
-I"/Library/Frameworks/R.framework/Versions/3.6/Resources/library/Rcpp/include" 
-I"/Library/Frameworks/R.framework/Versions/3.6/Resources/library/RcppArmadillo/include" 
-I"/Library/Frameworks/R.framework/Versions/3.6/Resources/library/ramcmc/include" 
-I"/Library/Frameworks/R.framework/Versions/3.6/Resources/library/sitmo/include" 
-isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk 
-I/usr/local/include -fopenmp -fPIC  -Wall -g -O2  -c R_approx.cpp -o 
R_approx.o
clang: error: unsupported option '-fopenmp'
make: *** [R_approx.o] Error 1
ERROR: compilation failed for package ‘bssm’
* removing 
‘/private/var/folders/mh/mrm_14nx19g13lsnj9zmvwjr0000gn/T/RtmppA2gBg/Rinst24427c5cbfeb/bssm’
       -----------------------------------
ERROR: package installation failed